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RS AGARWAL SOLUTION | CLASS 7TH | CHAPTER-4| Rational Numbers | EDUGROWN

Exercise 4A

Question 1.
Solution:
(i) Rational numbers: The numbers of the form pq where p and q are integers and q ≠ 0, are called rational numbers.
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 1
(iv) Yes, there is one rational number (0) which is neither positive nor negative.

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 2
(viii) 01 are all rational number but 10 and 00 are not rational number as their denominator is zero.

Question 3.
Solution:
(i) Numerator = 8, denominator =19
(ii) Numerator = 5, denominator = – 8
(iii) Numerator =-13, denominator =15
(iv) Numerator = – 8, denominator = -11
(v) Numerator = 9, denominator = 1

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 3

Question 5.
Solution:
According to the definition, a rational number is positive if both of numerator and denominator have same signs. Therefore
(iii), (iv) and (vi) 8 are positive rational numbers.

Question 6.
Solution:
According to the definition, a rational number is negative if numerator and denominator have opposite sign. Therefore.
(iii), (iv), (v), (vi) are all negative rational numbers.

Question 7.
Solution:
Equivalent rational numbers of each are given below:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 4

Question 8.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 5

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 6

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 7

Question 11.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 8

Question 12.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 9

Question 13.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 10

Question 14.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 11

Question 15.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 13

Question 16.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 14

Question 17.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 15

Question 18.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 18

Question 19.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 20

Question 20.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 23

Question 21.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4A 25

Exercise 4B

Question 1.
Solution:
(i) Draw a number line and locate a point O on it. Let it represent 0 Now 13 has been presented on the number line given below.
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 1
(ii) Draw a number line and locate a point O on it. Let it represent 0. The number 27 has been represented on the number line given below:

(iii) Draw a number line and locate a point O on it. Let it represent 0. The number 73 has been represented on the number line given below:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 3
(iv) Draw a number line and locate a point O on it. Let it represent 0. The number 73 has been represented on it as given below:

(v) Draw a number line and locate a point O on it. Let it represented 0. The number 378 has been represented on it as given below:
378 = 458
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 5
(vi) Draw a number line and locate a point O on it. Let it represent 0. The number −13 has been represented on it as given below:

(vii) Draw a number line and locate a point O on it. Let it represent 0. The number −34 has been represented on it is as given below:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 7
(viii) Draw a number line and locate a point on it. Let it represent 0. The number −127 has been represented on it as given below:

(ix) Draw a number line and locate a point O on it. Let it represent 0. The number 36−5 has been represented on it as given below:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 9
(x) Draw a number line and locate is point O on it. Let is represent 0. The number −439 has been represented on it as given below:

Question 2.
Solution:
(i) 56 or 0, 56 is greater as any positive number is always greater than 0.
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 11

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 12

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 18

Question 5.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 23

Question 6.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 30

Question 7.
Solution:
(i) True: All negative numbers lie on the left of 0.
(ii) False: All negative numbers lie on the left of 0.
(iii) True: All positive numbers lie on the right of 0 and all negative numbers on the left of 0.
(iv) False: −18−13 = 1813 which is positive and positive number lie on the left of 0.
(v) True: −5−8 = 58 which is positive and all positive number lie on the right of negative numbers.
(i), (iii) and (iv) are true.

Question 8.
Solution:
5 rational numbers between -3 and -2.
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 38

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 39

Question 10.
Solution:
L.C.M. of 5 and 2 = 10
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4B 41

Exercise 4C

Question 1.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4C 1

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4C 4

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4C 10

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4C 17

Question 5.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4C 24

Exercise 4D

Question 1.
Solution:
(i) Additive inverse of 5 = -5
(ii) Additive inverse of -9 = – (-9) = 9
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 1

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 3

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 9

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 15

Question 5.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 16

Question 6.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 17

Question 7.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 18

Question 8.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 19

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 21

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 22

Question 11.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 23

Question 12.
Solution:
The required number = −11 – 29
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 24

Question 13.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 25

Question 14.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 26

Question 15.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 27

Question 16.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4D 28

Exercise 4E

Question 1.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4E 1

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4E 4

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4E 7

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4E 9

Question 5.
Solution:
Cost of 1 metre of cloth
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4E 12

Question 6.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4E 13

Exercise 4F

Question 1.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 1
(vii) Reciprocal of -1 = -1
(viii) Reciprocal of 0 does not exist.

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 2

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 5

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 8

Question 5.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 9

Question 6.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 11

Question 7.
Solution:
Product of two number = 10
One number = -8
Second number = 10 ÷ (-8)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 12

Question 8.
Solution:
Product of two rational numbers = – 9
One number = -12
Second number = (-9) ÷ (-12)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 13

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 14

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 15

Question 11.
Solution:
Cloth required for 24 pairs of trousers =54 m
Cloth required for one pair = (54 ÷ 24) m
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 17

Question 12.
Solution:
Total length of rape = 30 m
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 18

Question 13.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4F 19

Exercise 4G

OBJECTIVE QUESTIONS
Mark (✓) against the correct answer in each of the following:
Question 1.
Solution:
(b)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 1

Question 2.
Solution:
(b)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 2

Question 3.
Solution:
(a)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 3

Question 4.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 4

Question 5.
Solution:
(b)

RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 6

Question 6.
Solution:
(a)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 7

Question 7.
Solution:
(a)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 8

Question 8.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 10

Question 9.
Solution:
(b)
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 11

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 12

Question 11.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 14

Question 12.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 15

Question 13.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 16

Question 14.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 17

Question 15.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 18

Question 16.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 19

Question 17.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 20

Question 18.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 21

Question 19.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 22

Question 20.
Solution:
RS Aggarwal Class 7 Solutions Chapter 4 Rational Numbers Ex 4G 23

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RS AGARWAL SOLUTION | CLASS 7TH | CHAPTER-3| Decimals | EDUGROWN

Exercise 3A

Question 1.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3A 1

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3A 2

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3A 3

Question 4.
Solution:
(i) 6.5, 16.03, 0.274, 119.4
In these decimals, the greatest places of decimal is 3
6.5 = 6.500
16.03 = 16.030
0. 274 = 0.274
119.4 = 119.400 are like decimals.
(ii) 3.5, 0.67, 15.6, 4
In these decimal, the greatest place of decimal is 2
3.5 = 3.50
0.67 = 0.67
15.6 = 15.60
4 = 4.00 are the like decimals

Question 5.
Solution:
(i) Among 78.23 and 69.85,
78.23 is greater than 69.85 (78 > 69)
78.23 > 69.85
(ii) Among 3.406 and 3.46,
3.406 is less than 3.46 (40 < 46)
3.406 < 3.46
(iii) Among 5.68 and 5.86,
5.68 is less than 5.86 (68 < 86)
5.68 < 5.86
(iv) Among 14.05 and 14.005
14.5 is greater than 14.005 (05 > 00)
14.5 >14.005
(v) Among 1.85 and 1.805,
1.85 is greater than 1.805 (85 > 80)
1.85 > 1.805
(vi) Among 0.98 and 1.07,
0.98 is less than 1.07 (0 < 1)
0.98 < 1.07

Question 6.
Solution:
(i) 4.6, 7.4, 4.58, 7.32, 4.06
Converting the given decimals into like decimals, we get:
4.60, 7.40, 4.58, 7.32, 4.06.
We see that 4.06 < 4.58 < 4.60 < 7.32 < 7.40.
Writing in ascending order, 4.06, 4.58, 4.6, 7.32, 7.4
(ii) 0.5, 5.5, 5.05, 0.05, 5.55
Converting the given decimals into like decimals, we get:
0. 50, 5.50, 5.05, 0.05, 5.55
We see that 0.05 < 0.50 < 5.05 < 5.50 < 5.55.
Writing in ascending order, 0.05, 0.50, 5.05, 5.5, 5.55
(iii) 6.84, 6.84, 6.8, 6.4, 6.08
Converting the given decimals into like decimals
6.84, 6.48, 6.80, 6.40, 6.08
We see that 6.08 < 6.40 < 6.48 < 6.80 < 6.84
Writing in ascending order,
6.08, 6.4, 6.48, 6.8, 6.84
(iv) 2.2, 2.202, 2.02, 22.2, 2.002
Converting them into like decimals
2.200, 2.202, 2.020, 22.200, 2.002 we see that
2.002 < 2.020 < 2.200 < 2.202 < 22.200
Now writing in ascending order,
2.002, 2.020, 2.2, 2.202, 22.2

Question 7.
Solution:
(i) 7.4, 8.34, 74.4, 7.44, 0.74
Converting them into like decimals,
7.40, 8.34, 74.40, 7.44, 0.74
we see that
74.40 > 8.34 > 7.44 > 7.40 > 0.74
Writing in descending order,
74.4, 8.34, 7.44, 7.4, 0.74
(ii) 2.6, 2.26, 2.06, 2.007, 2.3
Converting them into like decimals,
2.600, 2.260, 2.060, 2.007, 2.300
We see that
2.600 > 2.300 > 2.260 > 2.060 > 2.007
Writing in descending order,
2.6, 2.3, 2.26, 2.06, 2.007

Question 8.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3A 6

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3A 7

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3A 8

Exercise 3B

Question 1.
Solution:
Converting them into like decimals 16.00, 8.70, 0.94, 6.80 and 7.77
Now, adding them,
16.0 + 8.70 + 0.94 + 6.80 + 7.77 = 40.21
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 1

Question 2.
Solution:
Converting them into like decimals 18.600, 206.370, 8.008, 26.400, 6.900
Adding we get
18.600 + 206.370 + 8.008 + 26.400 + 6.900 = 266.278
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 2

Question 3.
Solution:
Converting them into like decimals, 63.50, 9.70, 0.80, 26.66, 12.17
Adding we get:
63.50 + 9.70 + 0.80 + 26.66 + 12.17 = 112.83
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 3

Question 4.
Solution:
Converting them into like decimals 17.400, 86.390, 9.435, 8.800, 0.060
Adding we get:
17.400 + 86.390 + 9.435 + 8.800 + 0.060 = 122.085
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 4

Question 5.
Solution:
Converting them into like decimals 26.900, 19.740, 231.769, 0.048
Now adding we get:
26.900 + 19.740 + 231.769 + 0.048 = 278.457
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 5

Question 6.
Solution:
Converting them into like decimals 23.800, 8.940, 0.078 and 214.600
Now adding we get:
23.800 + 8.940 + 0.078 + 214.600 = 247.418

Question 7.
Solution:
Converting them into like decimals.
6.606, 66.600, 666.000,0.066, 0.660
Now adding we get:
6.606 + 66.600 + 666.000 + 0.066 + 0,660 = 739.932
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 7

Question 8.
Solution:
9.090, 0.909, 99.900, 9.990, 0.099
Now adding we get:
9.090 + 0.909 + 99.900 + 9.990 + 0.099 = 119.988
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 8

Subtract:
Question 9.
Solution:
14.79 from 72.43
72.43 – 14.79 = 57.64
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 9

Question 10.
Solution:
Converting them into like decimals, We get
36.74 and 52.60
Now 52.60 – 36.74 = 15.86
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 10

Question 11.
Solution:
Converting them into like decimals, We get
13.876 and 22.000
22.000 – 13.876 = 8.124
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 11

Question 12.
Solution:
Converting them into like decimals, We get
15.079 and 24.160
24.160 – 15.079 = 9.081
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 12

Question 13.
Solution:
Converting them into like decimals We get
0.680 and 1.007
1.007 – 0.680 = 0.327
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 13

Question 14.
Solution:
Converting them into like decimals,
We get 0.4678 and 5.0500
5.0500 – 0.4678 = 4.5822
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 14

Question 15.
Solution:
Converting them into like decimals,
We get 2.5307 and 8.0000
8.0 – 2.5307 = 5.4693
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 15

Question 16.
Solution:
There are like decimals
9.1 – 6.732 = 2.269
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 16

Question 17.
Solution:
Converting them into like decimals,
We get 5.746 and 9.100
9.100 – 5.746 = 3.354
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 17

Question 18.
Solution:
Converting into like decimals, we get,
63.59 and 92.00
Required number = 92.00 – 63.58 = 28.42
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 18

Question 19.
Solution:
Converting into like decimals, we get:
8.100 and 0.813
Required number = 8.100 – 0.813 = 7.287
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 19

Question 20.
Solution:
Converting them into like decimals, we get: 32.67 and 60.10
Required number = 60.10 – 32.67 = 27.43
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 20

Question 21.
Solution:
Converting into like decimals, we get 74.3 and 26.87
Required number = 74.30 – 26.87 = 47.43
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3B 21

Question 22.
Solution:
Cost of notebook = Rs. 23.75
Cost ofpencil = Rs. 2.85
Costofpen =Rs. 15.90
Total cost = Rs. 42.50
Amount gave to the shop keeper = 50 rupees
Balance amount got = Rs 50.00 – Rs 42.50 = 7.50

Exercise 3C

Question 1.
Solution:
We know that by multiplying by 10, the decimal point is shifted one place to its right side.
(i) 73.92 x 10 = 739.2
(ii) 7.54 x 10 = 75.4
(iii) 84.003 x 10 = 840.03
(iv) 0.83 x 10 = 8.3
(v) 0.7 x 10 = 7.0
(vi) 0.032 x 10 = 0.32

Question 2.
Solution:
We know that by multiplying a decimal by 100, two decimal points are shifted to it right side
(i) 2.397 x 100 = 239.7
(ii) 6.83 x 100 = 683.0
(iii) 2.9 x 100 = 290
(iv) 0.08 x 100 = 8
(v) 0.6 x 100 = 60
(vi) 0.003 x 100 = 0.3

Question 3.
Solution:
We know that by multiplying a decimal by 1000, three places of decimal are shifted to its right.
(i) 6.7314 x 1000 = 6731.4
(ii) 0.182 x 1000 = 182
(iii) 0.076 x 1000 = 76
(iv) 6.25 x 1000 = 6250
(v) 4.8 x 1000=4800
(vi) 0.06 x 1000 = 60

Question 4.
Solution:
(i) 5.4 x 16 = 86.4 (One place of decimal)
(ii) 3.65 x 19 = 69.35 (Two place of decimal)
(iii) 0.854 x 12 = 10.2468 (Three place of decimal)
(iv) 36.73 x 48 = 1763.04 (Two places of decimal)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 1
(v) 4.125 x 86=354.750 (Three places of decimal)
= 354.75

Question 5.
Solution:
(i) 7.6 x 2.4= 18.24
{Sum of decimal places = 1 + 1 = 2}
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 4

Question 6.
Solution:
(i) 13 x 1.3 x 0.13 = 2.197
{Sum of decimal places = 1 + 2 = 3}
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 9
(ii) 2.4 x 1.5 x 2.5 = 9.000 = 9
{Sum of decimal places = 1 + 1 + 1 = 3}
(iii) 0.8 x 3.5 x 0.05 = 0.1400 = 0.14
{Sum of decimal places = 1 + 1 + 2 = 4}
(iv) 0.2 x 0.02 x 0.002 = 0.000008
{Sum of decimal places = 1 + 2 + 3 = 6}
(v) 11.1 x 1.1 x 0.11 = 1.3431
{Sum of decimal places = 1 + 1 + 2 = 4}
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 10
(vi) 2.1 x 0.21 x 0.021 = 0.00926
21 x 21 = 441
441 x 21 = 9261
{Sum of decimal places = 1 + 2 + 3 = 6}

Question 7.
Solution:
(i) (1.2)²= 1.2 x 1.2 = 1.44
{Sum of decimal places = 1 + 1 = 2}
(ii) (0.7)² = 0.7 x 0.7 = 0.49
{Sum of decimal places = 1 + 1 = 2}
(iii) (0.04)² = 0.04 x 0.04 = 0.0016
{Sum of decimal places = 2 + 2 = 4}
(iv) (0.11)² = 0.11 x 0.11 =0.0121
{Sum of decimal places = 2 + 2 = 4}

Question 8.
Solution:
(i) (0.3)³ = 0.3 x 0.3 x 0.3 = 0.027
{Sum of decimal places = 1 + 1 + 1 = 3}
(ii) (0.05)³= 0.05 x 0.05 x 0.05 = 0.000125
{Sum of decimal places = 2 + 2 + 2 = 6}
(iii) (1.5)³ = 1.5 x 1.5 x 1.5 = 3.375
{Sum of decimal places = 1 + 1 + 1 = 3}
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 11

Question 9.
Solution:
Distance covered in one hour = 62.5 km
Distance covered in 18 hours = 62.5 x 18 km = 1125.0 km

Question 10.
Solution:
Weight of one tin of oil = 16.8 kg
Weight of 45 tins = 16.8 x 45 kg = 756.0 kg = 756 kg
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 12

Question 11.
Solution:
Weight of wheat in one bag = 97.8 kg
weight of wheat in 500 bags = 97.8 x 500 kg = 48900.0 kg = 48900 kg
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 13

Question 12.
Solution:
Weight of one bag = 48.450 kg
Weight of 16 bags = 48.450 x 16 = 775.200 kg
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 14

Question 13.
Solution:
Quantity of sauce in one bottle = 0.845 kg
quantity of sauce in 72 bottles = 0.845 x 72 kg = 60.840 kg
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 15

Question 14.
Solution:
Quantity of jam in one bottle = 925 .
Quantity of jam in 25 bottles = 925 x 25 g = 23135 g = 23.125 kg
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 16

Question 15.
Solution:
Oil in one drum = 16.850 litres
Oil in 48 drums = 16.850 x 48 = 808.800 = 808.800 litres
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 17

Question 16.
Solution:
Cost of 1 kg rice = Rs 56.80
Cost of 16.25 kg of rice = Rs 56.80 x 16.25 = Rs 923.0000 = Rs 923
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 18

Question 17.
Solution:
Cost of one metre of cloth = Rs 108.5 0
Costof 18.5 metres of cloth = Rs 108.50 x 18.5 = Rs 2007.250 = Rs 2007.25
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 19

Question 18.
Solution:
Distance covered in one litre = 8.6 km
Distance covered in 36.5 litres = 8.6 x 36.5 km = 313.90 km = 313.9 km
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 20

Question 19.
Solution:
Charges for 1 km = Rs 9.80
Charges for 106.5 km = Rs 9.80 x 106.5 = Rs 1043.700 = Rs 1043.70
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3C 21

Exercise 3D

Question 1.
Solution:
We know that a decimal divided by 10, the decimal point is shifted to the left by one place. Therefore
(i) 131.6 ÷ 10 = 13.16
(ii) 32.56 ÷ 10 = 3.256
(iii) 4.38 ÷ 10 = 0.438
(iv) 0.34 ÷ 10 = 0.034
(v) 0.08 ÷ 10 = 0.008
(vi) 0.062 ÷ 10 = 0.0062

Question 2.
Solution:
We know that decimal divided by 100, the decimal point is shifted to the left by two place. Therefore
(i) 137.2 ÷ 100 = 1.372
(ii) 23.4 ÷ 100= 0.234
(iii) 4.1 ÷ 100 = 0.047
(iv) 0.3 ÷ 100 = 0.003
(v) 0.58 ÷ 100 = 0.0058
(vi) 0.02 ÷ 100 = 0.0002

Question 3.
Solution:
We know that a decimal divided by 1000, the decimal point is shifted to the left by three places. Therefore:
(i) 1286.5 ÷ 1000= 1.2865
(ii) 354.16 ÷ 1000 = 0.35416
(iii) 38.9 ÷ 1000 = 0.0389
(iv) 4.6 ÷ 1000 = 0.0046
(v) 0.8 ÷ 1000 = 0.0008
(vi) 2 ÷ 1000 = 0.002

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 1

Question 5.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 5

Question 6.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 12

Question 7.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 16

Question 8.
Solution:
Cost of 24 chairs = Rs. 9255.60
Cost of one chair = Rs. 9255.6024 = Rs. 385.65

Question 9.
Solution:
Length of cloth for one shirt = 1.8 m
Total length of piece of cloth = 45 m
Number of shirts will be = 45 ÷ 1.8
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 25

Question 10.
Solution:
A car covers in 2.4 litre = 22.8 km
It will cover in 1 litre = 22.82.4 km = 9.5 km

Question 11.
Solution:
Oil in one tin = 16.5 l
Total oil = 478.5 l
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 26

Question 12.
Solution:
Weight of 37 bags of sugar=3644.5 kg
Weight of one bag of sugar = 3644.5 ÷ 37
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 27

Question 13.
Solution:
Capacity of 69 buckets = 586.5 litres
Capacity of 1 bucket = 586.5 ÷ 69
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 28

Question 14.
Solution:
Number of pieces in 1.15 m = 1
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 29

Question 15.
Solution:
Total weight of cement = 1792.8 kg
Cement in one bag = 49.8 kg
Number of bags = 1792.8 ÷ 49.8
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 30

Question 16.
Solution:
Total thickness = 1.89 m = 189 cm
Thickness of one piece = 0.3 5 cm
Number of pieces = 189 ÷ 0.35
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 32

Question 17.
Solution:
Product of two decimals = 261.36
One decimal = 17.6
Second decimal = 261.36 ÷ 17.6
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3D 33

Exercise 3E

OBJECTIVE QUESTIONS
Mark (✓) against the correct answer in each of the following:
Question 1.
Solution:
(b)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 1

Question 2.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 2

Question 3.
Solution:
(b)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 3
= 208100 = 2.08

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 4

Question 5.
Solution:
(b) 70g = 701000 = 0.07 kg

Question 6.
Solution:
(c) 5 kg 6 g = 561000 kg = 5.006 kg

Question 7.
Solution:
(c) 2 km 5 m = 251000 km = 2.005 km

Question 8.
Solution:
(c)
1.007 – 0.7 = 1.007 – 0.700 = 0.307

Question 9.
Solution:
(b)
0.1 – 0.03 = 0.10 – 0.03 = 0.07

Question 10.
Solution:
(c)
3.5 – 3.07 = 3.50 – 3.07 = 0.43

Question 11.
Solution:
(c)
0.23 x 0.3 = 0.069

Question 12.
Solution:
(b)
0.02 x 30 = .60 = .6

Question 13.
Solution:
(b)
0.25 x 0.8 = 0.200 = 0.2

Question 14.
Solution:
(c)
0.4 x 0.4 x 0.4 = 0.064

Question 15.
Solution:
(b)
1.1 x .1 x .01 = .0011

Question 16.
Solution:
(a)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 5

Question 17.
Solution:
(b)
1.02 ÷ 6 = 1.026 = 0.17

Question 18.
Solution:
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 6

Question 19.
Solution:
(b)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 7

Question 20.
Solution:
(a)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 8

Question 21.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 3 Decimals Ex 3E 9

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RS AGARWAL SOLUTION | CLASS 7TH | CHAPTER-2 | Fractions | EDUGROWN

Exercise 2A

Question 1.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 1

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 3

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 6

Question 4.
Solution:
Reenu get 27 of an apple while Sonal gets 45 part of it
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 9

Question 5.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 10

Question 6.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 15

Question 7.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 19

Question 8.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 23

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 24

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 25

Question 11.
Solution:
For finding the required fraction, we have to subtract 735 from 18
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 26

Question 12.
Solution:
For finding the required fraction we should subtract 7415 from 825
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 27

Question 13.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 28

Question 14.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 29

Question 15.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 30

Question 16.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2A 31

Exercise 2B

Question 1.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 1

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 4

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 7

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 11

Question 5.
Solution:
Cost of 1 metre pf cloth
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 12

Question 6.
Solution:
Distance covered in 1 hour
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 13

Question 7.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 14

Question 8.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 15

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 16

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 17

Question 11.
Solution:
Weight of Amit = 35 kg.
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 18

Question 12.
Solution:
Total number of students in a class = 42
Number of boys = 57 of 42 = 5 x 6 = 30
Number of girls = 42 – 30 = 12

Question 13.
Solution:
Sapna total income for one month = Rs 24000
Amount spent = 78 of her income
= 78 x 24000
= Rs (7 x 3000) = Rs 21000
Amount deposited in the bank per month = Rs 24000 – 21000 = Rs 3000

Question 14.
Solution:
Length of each side of a square
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 19

Question 15.
Solution:
Length of rectangular field (l)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2B 20

Exercise 2C

Question 1.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 1

Question 2.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 2

Question 3.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 4

Question 4.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 6

Question 5.
Solution:
Total weight of 18 boxes
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 7

Question 6.
Solution:
Total amount of oranges=Rs 378
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 8

Question 7.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 10

Question 8.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 11

Question 9.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 13

Question 10.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 14

Question 11.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 16

Question 12.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 17

Question 13.
Solution:
Total quantity of milk = 24 litres
and quantity of milk got by one student = 25 litres
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 19

Question 14.
Solution:
Quantity of water in a bucket
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 20

Question 15.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 22

Question 16.
Solution:
Product of two numbers = 42
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 23

Question 17.
Solution:
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2C 24

Exercise 2D

OBJECTIVE QUESTIONS
Mark (√) against the correct answer in each of the following:
Question 1.
Solution:
(c)
Denominator in (a) and (b) is 10
These are decimal fractions
But denominator of (c) is 3
103 is a vulgar fraction

Question 2.
Solution:
(c)
710 and 79 are proper fractions as each of these have numerator less than its denominator
97 is improper fraction

Question 3.
Solution:
(a)
105112 is reducible fraction because HCF 112 of 105 and 112 is 7

Question 4.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 1

Question 5.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 2

Question 6.
Solution:
(d)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 4

Question 7.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 5

Question 8.
Solution:
(d)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 6

Question 9.
Solution:
(d)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 7

https://googleads.g.double

Question 10.
Solution:
(b)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 8

Question 11.
Solution:
(d)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 9

Question 12.
Solution:
(c)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 10

Question 13.
Solution:
(d)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 11

Question 14.
Solution:
(d)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 12

Question 15.
Solution:
(b)
The correct statement will be
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 13

Question 16.
Solution:
(c)
A car runs in 1 litre of petrol = 16 km
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 14

Question 17.
Solution:
(a)
RS Aggarwal Class 7 Solutions Chapter 2 Fractions Ex 2D 15

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RS AGARWAL SOLUTION | CLASS 7TH | CHAPTER-1 | Integers | EDUGROWN

Exercise 1A

Question 1.
Solution:
(i) 15 + (-8) =15 – 8 = 7
(ii) (-16) +9 = -7
(iii) (-7) + (-23)= -7 – 23 = -30
(iv) (-32) + 47 = -32 + 47 = 15
(v) 53 + (-26) = 53 – 26 = 27
(vi) (-48) + (-36) = -48 – 36 = -84

Question 2.
Solution:
(i) 153 and -302 = 153 + (-302) = 153 – 302 = -149
(ii) 1005 and -277 = 1005 + (-277) = 1005 – 277 = 728
(iii) -2035 and 297 = -2035 + 297 = – 1738
(iv) -489 and -324 = -489 + (-324) = -489 – 324 = -813
(v) -1000 and438 = -1000 + 438 = -562
(vi) -238 and 500 = -238 + 500 = 262

Question 3.
Solution:
Additive inverse of
(i) -83 is – (-83) = 83
(ii) 256 is -256
(iii) 0 is 0
(iv) -2001 is – (-2001) = 2001

Question 4.
Solution:
(i) 28 from – 42 = -42 – (28) = -42 – 28 = -70
(ii) – 36 from 42 = 42 – (-36) = 42 + 36 = 78
(iii) -37 from -53 = -53 – (-37) = -53 + 37= -16
(iv) -66 from -34 = -34 – (-66) = -34 + 66 = 32
(v) 318 from 0 = 0 – (318) = -318
(vi) -153 from -240= -240 – (-153) = -240 + 153 = -87
(vii) -64 from 0 = 0 – (-64) = 0 + 64 = 64
(viii) – 56 from 144 = 144 – (-56) = 144 + 56 = 200

Question 5.
Solution:
– 34 – (-1032 + 878)
= -34 – (-154) = -34 + 154 = 120

Question 6.
Solution:
38 + (-87) – 134
= (38 – 87) – 134
= -49 – 134 = -183

Question 7.
Solution:
(i) {(-13) + 27} + (-41) = (-13) + {27 + (-41)} (By Associative Law of Addition)
(ii) (-26) + {(-49) + (-83)} = {(-26) + (-49)} +(-83) (By Associative Law of Addition)
(iii) 53 + (-37) = (-37) + (53) (By Commutative Law of Addition)
(iv) (-68) + (-76) = (-76) + (-68) (By Commutative Law of Addition)
(v) (-72) + (0) = -72 (Existence of Additive identity)
(vi) -(-83) = 83
(vii) (-60) – (………) = -59 => -60 – (-1) = -59
(viii) (-31) + (……….) = -40 => -31 + (-9) = -40

Question 8.
Solution:
{-13 – (-27)} + {-25 – (-40)}
= {-13 + 27} + {-25 + 40}
= 14 + 15 = 29

Question 9.
Solution:
36 – (- 64) = 36 + 64 = 100
(-64) – 36= -64 – 36 = -100
They are not equal

Question 10.
Solution:
(a + b) + c = {-8 + (-7)} + 6 = (-8 – 7) + 6 = -15 + 6 = -9
and a + (b + c) = -8 + (-7 + 6) = -8 + (-1) = -8 – 1 = -9 Hence proved

Question 11.
Solution:
LHS = (a -b) = -9 – (-6) = -9 + 6 = -3
RHS = (b – a) = -6 – (-9) = -6 + 9 = 3
LHS ≠ RHS.
Hence (a – b) ≠ (b – a)

Question 12.
Solution:
Sum of two integers = -16
One integer = 53
Second integer = -16 – (53) = -16 – 53 = (-69)

Question 13.
Solution:
Sum of two integers = 65
One integer = -31
Second integer = 65 – (-31) = 65 + 31 = 96

Question 14.
Solution:
Difference of a and (-6) = 4
a – (-6) = 4
⇒ a + 6 = 4
⇒ a = 4 – 6
⇒ a = -2

Question 15.
Solution:
(i) We can write any two integers having opposite signs
e.g. 5, -5
Sum = 5 + (-5) = 5 – 5 = 0
(ii) The sum is a negative integer
The greater integer must be negative and smaller integer be positive
e.g. -9, 6
Sum = -9 + 6 = -3
(iii) The sum is smaller than the both integers
Both integer will be negative -4, -6
Sum = -4 + (-6) = -4 – 6 = -10
(iv) The sum is greater than the both integers
Both integers will be positive
e.g. 6, 4
(v) The sum oftwo integers is smaller than one of these integers
The greater number will be positive and smaller be negative
e.g. 6, -4
Sum = 6 + (-4) = 2

Question 16.
Solution:
(i) False: Because, all negative integers are less than zero.
(ii) False: -10 is less than -7.
(iii) Tme: Every negative integer is less than zero.
(iv) True : Sum of two negative integers is negative.
(v) False: It is not always true.

Exercise 1B

Question 1.
Solution:
(i) 16 by 9 = 16 x 9 = 144
(ii) 18 by -6 = 18 x (-6) = -108
(iii) -36 by -11 = 36 x (-11) = -396
(iv) -28 by 14 = -28 x 14 = -392
(v) -53 by 18 = -53 x 18 = -954
(vi) -35 by 0 = -35 x 0 = 0
(vii) 0 by -23 = 0 x (-23) = 0
(viii) -16 by -12 = (-16) x (-12) = 192
(ix) -105 by -8 = -105 x (-8) = 840
(x) -36 by -50 = (-36) x (-50) = 1800
(xi) -28 by -1 = (-28) x (-1) = 28
(xii) 25 by -11 = 25 x -11 = -275

Question 2.
Solution:
(i) 3 x 4 x (-5) = 12 x (-5) = -60 = 60
(ii) 2 x (-5) x (-6) = (-10) x (-6) = 60
(iii) (-5) x (-8) x (-3) = 40 x (-3) = -120
(iv) (-6) x 6 x (-10) = (-36) x (-10) = 360
(v) 7 x (-8) x 3 =(-56) x 3 = -168
(vi) (-7) x (-3) x 4 = 21 x 4 = 84

Question 3.
Solution:
(i) (-4) x (-5) x (-8) x (-10) = (4 x 5) x (8 x 10)
{Number of negative integers is even}
= 20 x 80 = 1600
(ii) (-6) x (-5) x (-7) x (-2) x (-3)
Here number of negative integers is odd
= (-1) [6 x 5 x 7 x 2 x 3]
= (-1) (1260) = -1260
(iii) (-60) x (-10) x (-5) x (-1)
Here number of negative integers is even
= 60 x 10 x 5 x 1
= 3000
(iv) (-30) x (-20) x (-5)
Here number of negative integers is odd
= (-1) (30 x 20 x 5) = -1 x 3000 = -3000
(v) (-3) x (-3) x (-3) x …6 times
Here number of negative integers is even
= 3 x 3 x 3 x 3 x 3 x 3 = 729
(vi) (-5) x (-5) x (-5) x …5 times
Here number of negative integers is odd
= (-1) (5 x 5 x 5 x 5 x 5)
= (-1) (3125) = – 3125
(vii) (-1) x (-1) x (-1) x …200 times
Here number of negative integers is even
= 1 x 1 x 1 x 1 x 200 times = 1
(viii) (-1) x (-1) x (-1) x …171 times
Here number of negative integers is odd
= (-1) x (1 x 1 x 1 x ……… 171 times)
= -1 x 1 = -1

Question 4.
Solution:
Number of negative integers = 90
which is positive and 9 integers are positive
The sign of the product will be positive

Question 5.
Solution:
Number of negative integers = 103 which is negative
Product will be negative

Question 6.
Solution:
(i) (- 8) x 9 + (- 8) x 7
= (-8) {9 + 7}
= -8 x 16 = -128
(ii) 9 x (-13) + 9 x (-7)
= 9 x (-13 – 7)
= 9 x (-20) = – 180
(iii) 20 x (-16) + 20 x 14 = 20 x {-16 + 14}
= 20 x (-2)= -40
(iv) (-16) x (-15) + (-16) x (-5)
= (-16) x {-15 – 5}
= (-16) x (-20) = 320
(v) (-11) x (-15)+ (-11) x (-25)
-(-11) x {-15 – 25}
= (-11) x (-40) = -440
(vi) 10 x (-12)+ 5 x (-12)
= (-12) {10 + 5} = (-12) x 15 = -180
(vii) (-16) x (-8) + (-4) x (-8)
= (-8){-16 – 4} = (-8) x (-20) = 160
(viii) (-26) x 72 + (-26) x 28
= (-26) (72 + 28) = (-26) x 100 = -2600

Question 7.
Solution:
(i) (-6) x (………) = 6 ⇒ (-6) x (-1) = 6
(ii) (-18) x (………) = (-18) ⇒ (-18) x (1) = (-18)
(iii) (-8) x (-9) = (-9) x (……….) ⇒ (-8) x (-9) = (-9) x (-8) (By Commutative Law of Multiplication)
(iv) 7 x (-3) = (-3) x (……….) ⇒ 7 x (-3) = (-3) x (7) (By Commutative Law of Multiplication)
(v) {(-5) x 3} x (-6) = (………) x {3 x (-6)} ⇒ {(-5) x 3} x (-6) = (-5) x {3 x (-6)} (By Associative Law of Multiplication)
(vi) (-5) x (……….) = 0 ⇒ (-5) x (0) = 0 (By Property of Zero)

Question 8.
Solution:
Number of questions in a test =10
Marks awarded for every correct answer = 5
and marks deducted for every wrong answer = 2 (-2 is given)
(i) Ravi gets 4 correct and 6 incorrect answers
Total marks obtained by him = 4 x 5 – 6 x 2 = 20 – 12 = 8
(ii) Reenu gets 5 correct and 5 incorrect answers
Total marks obtained by her = 5 x 5 – 5 x 2 = 25 – 10= 15
(iii) Heena gets 2 correct and 5 incorrect answers
She gets marks = 2 x 5 – 5 x 2 = 10 – 10 = 0

Question 9.
Solution:
(i) True: As product of a positive and a negative integer is negative.
(ii) False: The product of two negative integers is positive.
(iii) True.
(iv) False: As multiplication of an integer and (-1) is negative.
(v) True as a x b = b x a.
(vi) True as (a x b) x c = a x (b x c)
(vii) False: It is not possible except integer 1.

Exercise 1C

Question 1.
Solution:
(i) 65 by -13 = 65 ÷ (-13) = -5
(ii) -84 by 12 = -84 ÷ 12 = -7
(iii) -76 by 19 = -76 ÷ 19 = -4
(iv) -132 by 12 = -132 ÷ 12 = -11
(v) -150 by 25 = -150 ÷ 25 = -6
(vi) -72 by -18= -72 ÷ (-18)
(vii) -105 by -21 = -105 ÷ (-21) = 5
(viii) -36 by -1 = -36 ÷ (-1) = 36
(ix) 0 by -31 = 0 ÷ (-31) = 0
(x) -63 by 63 = -63 ÷ 63 = -1
(xi) -23 by -23 = -23 ÷ (-23)
(xii) -8 by 1 = -8 ÷ 1 = -8

Question 2.
Solution:
(i) 72 ÷ (………) = -4
⇒ 72 ÷ (-4) = -18
72 + (-18) = -4
(ii) -36 ÷ (………) = -4
⇒ -36 ÷ (-4) = 9
-36 ÷ (9) = -4
(iii) (………) ÷ (-4) = 24
⇒ -4 x 24 = -96
(-96) ÷ (-4) = 24
(iv) (……….) ÷ 25 = 0
(…….) ÷ 25 = 0 {0 ÷ a = 0}
(v) (………) ÷ (-1) = 36
⇒ 36 x (-1) = -36
(-36) ÷ (-1) = 36
(vi) (………..) + 1 = 37
⇒ (-37) x 1 = -37
(-37) ÷ 1 = -37
(vii) 39 ÷ (……….) = -1
⇒ 39 ÷ (-1) = -39
39 ÷ (-39) = -1
(viii) 1 ÷ (………) = -1
⇒ -1 ÷ 1 = -1
1 ÷ (-1) = -1
(ix) -1 + (………) = -1
-1 ÷ (1) = -1

Question 3.
Solution:
(i) True : as zero divided by non zero integer is zero.
(ii) False : as division by zero is not meaning full
(iii) False : as (-5) ÷ (-1) = 5 (product will be positive)
(iv) True : as -a ÷ 1 = -a
(v) False : as (-1) ÷ (-1) = 1
(vi) True.

Exercise 1D

OBJECTIVE QUESTIONS
Mark (√) against the correct answer in each of the following.
Question 1.
Solution:
(c)
6 – (-8) = 6 + 8 = 14

Question 2.
Solution:
(b)
-9 – (-6) = -9 + 6 = -3

Question 3.
Solution:
(d)
-3 + 5 = 2

Question 4.
Solution:
(a)
-1 – (+5) = -1 – 5 = -6

Question 5.
Solution:
(a)
-2 – (4) = -2 – 4 = -6

Question 6.
Solution:
(b)
-4 – (+4) = -4 – 4 = -8

Question 7.
Solution:
(b)
-3 – (-5) = -3 + 5 = 2

Question 8.
Solution:
(c)
-3 – (-9) = -3 + 9 = 6

Question 9.
Solution:
(c)
-5 – (6) = -5 – 6 = -11

Question 10.
Solution:
(c)
-8 – (-13) = -8 + 13 = 5

Question 11.
Solution:
(a)
(-36) ÷ (-9) = 4

Question 12.
Solution:
(b)
0 ÷ (-5) = 0
(Zero divided by any integer other than zero, is zero)

Question 13.
Solution:
(c)
Division by zero is not defined

Question 14.
Solution:
(b)

Question 15.
Solution:
(b)
-3 + 9 = 6

Question 16.
Solution:
(a)
-4 – (-10) = -4 + 10 = 6

Question 17.
Solution:
(a)
Sum = 14
One integer = -8
Second = 14 – (-8) = 14 + 8 = 22

Question 18.
Solution:
(c)

Question 19.
Solution:
(b)
(-15) x 8 + (-15) x 2
= (-15) {8 + 2}
= -15 x 10 = -150

Question 20.
Solution:
(b)
(-12) x 6 – (-12) x 4 = (-12) (6 – 4) = -12 x 2 = -24

Question 21.
Solution:
(b)
(-27) x (-16)+ (-27) x (-14)
= (-27) {-16 – 14}
= (-27) x (-30)
= 810

Question 22.
Solution:
(a)
30 x (-23) + 30 x 14
= 30 x (-23 + 14)
= 30 x (-9)
= -270

Question 23.
Solution:
(c)
Sum of two integers = 93
One integer = -59
Second = 93 – (-59) = 93 + 59 = 152

Question 24.
Solution:
(b)
(?) ÷ (-18) = -5
Let x ÷ (-18) = -5
⇒ x−18 = -5
⇒ x = (-5) x (-18) = 90

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CHAPTER – 10 Respiration in Organisms | CLASS 7TH | NCERT SCIENCE IMPORTANT QUESTIONS & MCQS | EDUGROWN

SCIENCE IMPORTANT QUESTIONS & MCQS FOR CLASS 7th

Get Chapter Wise MCQ Questions for Class 7 Science with Answers prepared here according to the latest CBSE syllabus and NCERT curriculum. Students can practice CBSE Class 7 Science MCQs Multiple Choice Questions with Answers to score good marks in the examination. Students can also visit the most accurate and elaborate NCERT Solutions for Class 7Science. Every question of the textbook has been answered here.

Chapter - 10 Respiration in Organisms

MCQs

Question 1.
Sometimes when we do heavy exercise, anaerobic respiration takes place in our muscle cells. What is produced during this process?
(a) alcohol and lactic acid
(b) alcohol and CO₂
(c) lactic acid and CO₂
(d) lactic acid only

Answer

Answer: (d) lactic acid only

Question 2.
Yeast is used in wine and beer industries because it respires.
(a) aerobically producing oxygen
(b) aerobically producing alcohol
(c) anaerobically producing alcohol
(d) anaerobically producing CO₂

Answer

Answer: (c) anaerobically producing alcohol

Question 3.
During the process of exhalation, the ribs move
(a) down and inwards
(b) up and inwards
(c) down and outwards
(d) up and outward

Answer

Answer: (a) down and inwards

Question 4.
Breathing is a process that
(i) provides O₂ to the body.
(ii) breaks down food to release energy.
(iii) helps the body to get rid of CO₂
(iv) produces water in the cells.
Which of the following gives the correct combination of functions of breathing?
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (ii) and (iv)

Answer

Answer: (c) (i) and (iii)

Question 5.
Which are the gases involved in breathing?
(a) O₂ and NO₂
(b) O₂ and SO₂
(c) O₂ and O₃
(d) O₂ and CO₂

Answer

Answer: (d) O₂ and CO₂

Question 6.
Name the organ of the body in which the blood is oxygenated.
(a) Heart
(b) Lungs
(c) Lever
(d) Pancreas

Answer

Answer: (b) Lungs

Question 7.
After heavy exercise, due to the accumulation of which substance we get muscle cramps ?
(a) Malaic acid
(b) Fumaric acid
(c) Lipoic acid
(d) Lactic acid

Answer

Answer: (d) Lactic acid

Question 8.
Yeasts are used in
(a) wine and beer industry
(b) bakery
(c) in both
(d) none of these

Answer

Question 9.
In the following figure of respiratory system organs labelled by 1 and 2 are respectively:

(a) Tracheae, Lungs
(b) Lungs, Tracheae
(c) Nasal cavity, Lungs
(d) Lungs, Nasal cavity

Answer

Answer: (a) Tracheae, Lungs

Question 10.
Breathing rate in human beings in normal condition is
(a) 12-15 times in a minute
(b) 15-18 times in a minute
(c) 18-22 times in a minute
(d) 22-25 times in a minute

Answer

Answer: (b) 15-18 times in a minute

Match the following:

Column A	Column B
(i) Unicellular organisms	(a) Skin
(ii) Plants	(b) Spiracles
(iii) Earthworm, Leech	(c) Cell membrane
(iv) Insects	(d) Lungs, skin
(v) Frog	(e) Stomata
(vi) Mammals	(f) Gills
(vii) Fish	(g) Lungs

Answer

Answer:

Column A	Column B
(i) Unicellular organisms	(c) Cell membrane
(ii) Plants	(e) Stomata
(iii) Earthworm, Leech	(a) Skin
(iv) Insects	(b) Spiracles
(v) Frog	(d) Lungs, skin
(vi) Mammals	(g) Lungs
(vii) Fish	(f) Gills

Fill in the blanks

1. In higher animals, respiration occurs through ……………….

Answer

Answer: lungs

2. The food has ………………. which is released during ……………….

Answer

Answer: stored energy, respiration

3. Yeasts can survive in the absence of air. They are called ……………….

Answer

Answer: anaerobes

4. The accumulation of ………………. causes muscle cramps.

Answer

Answer: lactic acid

5. The taking in of air rich in oxygen into body is called ……………….

Answer

Answer: inhalation

6. Breathing involves the movement of the ………………. and the ……………….

Answer

Answer: diaphragm, rib-cage

Choose the true and false statements from the following:

1. All living organisms respire to get energy from food.

Answer

Answer: True

2. Cellular respiration takes place in the cells of all organisms.

Answer

Answer: True

3. Muscles can also respire anaerobically.

Answer

Answer: True

4. During heavy exercise the breathing rate declines.

Answer

Answer: False

5. Breathing involves the upward movement of the diaphragm.

Answer

Answer: False

6. The percentage of carbon dioxide is higher in exhaled air in comparison to inhaled air.

Answer

Answer: True

7. Roots take up air from the air spaces present between the soil particles.

Answer

Answer: True

Question 1.
What are the end products of aerobic respiration.
Answer:
During aerobic respiration, carbon dioxide and water are released along with a large amount of energy.

Question 2.
The cellular respiration process takes place in which cell organelle?
Answer:
Cellular respiration takes place in the mitochondria of the cell.

Question 3.
Name the end products of anaerobic respiration in yeast.
Answer:
The end product formed during anaerobic respiration in yeast are

Ethyl alcohol
Carbon dioxide
Energy

Question 4.
In some animals, exchange of gases takes place through its thin and moist skin. Name one such animal. [HOTS]
Answer:
Earthworm is an animal where exchange of gases during breathing or respiration takes place through its thin and moist skin.

Question 5.
Give the name of respiratory organs in following animals.
(a) Fish
(b) Human being
Answer:
The respiratory organ of the following animals are as follows
(a) Fish – Gills
(b) Human being – lungs

Question 6.
Our nostrils has hair and mucous. What is the need to have them in our nasal cavity? [HOTS]
Answer:
Our nostrils possess hairs and mucous lining. These help in preventing dirt, dust and germs from entering our respiratory system.

Question 7.
Sometimes we see that farmers loosen the soil. What is the reason behind it?
Answer:
The farmers sometimes loosen the soil. This helps the root to respire through the air present in the space between soil particles.

Question 8.
Various organs constitute the respiratory system of human. These organs are located according to their functions. Identify them.
Answer:
The various organs in the respiratory system of human are nostrils, nasal passage, nasal cavity, windpipe and lungs.

Question 9.
The vocal ability of humans is the responsibility of an organ commonly known as voice box. What is its scientific name?
Answer:
The organ that is responsible for speech is larynx or voice box. It lies between pharynx and trachea.

Question 10.
What changes are observed in diaphragm during inhalation?
Answer:
During the process of inhalation diaphragm contracts and moves downwards.

Question 11.
When we exhale or breathe out, percentage of a certain gas is high. Name the gas.
Answer:
The gas, carbon dioxide is in higher percentage or amount, when we exhale or breathe out.

Question 12.
In the experiment, where we exhale into lime water containing glass. What changes were observed by you?
Answer:
When we exhale into lime water its colour changes, into slightly milky white because exhaled air contains CO₂.

Question 13.
Insects have a special organ present to carry out respiration. What is that organ called?
Answer:
Insects possess special organ called spiracles for respiration.

Question 14.
Name the respiratory organs in frogs.
Answer:
Frogs respire through their moist skin as well as through a pair of lungs.

Question 15.
Certain small pores are present on the surface of plant through which gaseous exchange occurs. Identify these pores?
Answer:
Stomata are the tiny pores that are present on the surface of plant through which gaseous exchange occurs.

Question 16.
What happens to your breathing rate when you
(a) exercise
(b) go to sleep
Answer:
The breathing rate during exercise is increased while during sleep it goes down.

Question 17.
Floor of chest cavity refers to which organ of respiration?
Answer:
Diaphragm is known as the floor of chest cavity.

Question 18.
Respiration is a continous process. What is the need for it to be continuous rather than being like photosynthesis?
Answer:
Process of respiration yields energy which is required to perform a variety of routine activities. Thus, it needs to be a continuous process.

Question 19.
A part from stomata another structure is used by plants to respire. Name that structure.
Answer:
Lenticels.

Question 20.
Name the organisms which respire using anaerobic mode. Give an example of ane such organism.
Answer:
Anaerobes respire using anaerobic mode. Yeast is an organism respiring anaerobically.

Question 21.
Explain cellular respiration.
Answer:
The process of braeakdown of food in the cell with the release of energy is called cellular respiration.

Question 22.
All organisms breathe in O₂ and CO₂. Should be less O₂and excess of CO₂ in our environment. [HOTS]
Answer:
The CO₂ released by us is used by plants during the process of respiration and they release O₂ as a result of this process which is used by rest of the organisms.

Question 23.
The process of fermentation is based on which principle?
Answer:
Anaerobic respiration.

Question 24.
When oxygen enters our body it combines with haemoglobin to form a new substance. What is that new product.
Answer:
Oxyhaemoglobin.

Question 25.
Is the rate of breathing same for all the respiring organism?
Answer:
No, different organisms respire at different rate because they all perform different activities at all times.

Question 26.
Which gas present in air is essential for aerobic respiration? What is the role of this gas during respiration?
Answer:
Oxygen present in air is essential for aerobic respiration.
Oxygen breaks down food and releases energy during respiration.

Question 27.
On a very cold morning, Boojho and Paheli were talking with each other as they walked down to their school. They observed that the air coming out of their mouth looked like smoke. They were asumed and wondered how it happened. Help them to find the answer. [HOTSl
Answer:
On a cold day, the warm and moist air exhaled by us condenses into moist when it comes in contact with the cold air of the atmosphere, this looks like white smoke.

Respiration in Organisms Class 7 Science Extra Questions Short Answer Type Questions

Question 1.
Pick the odd one out from each of the groups given below on the basis of respiratory organs. Give reason for your answer.
(a) Cockroach, grasshopper, snail, ant
(b) Lizard, cow, earthworm, snake
(c) Crocodile, whale, dolphin, fish
(d) Snake, tadpole, crow, goat [NCERT Exemplar]
Answer:
(a) Snail, as it does not breathe by means of trachea.
(b) Earthworm, because it breathes through its skin and it does not have lungs.
(c) Fish, as most fish breathe through their gills and do not have lungs.
(d) Tadpole, as it breathes through gills and do not have lungs.

Question 2.
Insects and leaves of a plant have pores through which they exchange gases with the atmosphere. Can you write two points of differences between these pores with respect to their position, number and extension into the body?
Answer:
Pores present on the sides of insects are called spiracles while pores present on the surface of leaves are called stomata. These structures are responsible for the exchange of gases with the atmosphere.
Differences between these two are as follows

Spiracles are fewer in number as compared to stomata.
Spiracles lead to an extensive network of tracheal system which is absent in the leaves.

Question 3.
Frogs are amphibians. They survive on land and water, do they have any respiratory issue? How does frog breathe when they are in water? Do they possess lungs? Explain the role of lungs in frogs.
Answer:
Frog breathe by their moist skin and through lungs also. So, they do not have any, respiratory issue.
When frog enters into water, the skin of frog helps in respiration.
The oxygen rich air enters through the skin. When the frog is on land, a pair of lungs helps in respiration.
The lungs take the oxygen rich air through the nostrils from where the oxygen is absorbed by the blood and carried throughout the body. The carbon dioxide from the blood is diffused back through the skin and lungs into the atmosphere.

Question 4.
After we work hard or perform physical activity, we feel hungry. Explain why.
Answer:
When we work hard or perform physical activity (like running, swimming, cycling), we need mdre energy. To fulfil the energy requirement, we breathe faster. Fast breathing helps in supply of more oxygen to our cells. Due to this, rate of breakdown of food increases and more energy is released. The rapid breakdown of food makes us to feel more hungry.

Question 5.
Name one organism who respires anaerobically. How does this organism help in beverage and baking industry?
Answer:
Yeast is a single celled organism. During anaerobic respiration (also called fermentation), yeast produces ethanol or alcohol as a byproduct which is used in making wine and beer. The carbon dioxide produced by yeast is used in the bread making industry. The CO₂ gas released during this process causes the bread dough to rise.

Question 6.
Smoking is considerd harmful due to certain effects. Explain in brief. [HOTS]
Answer:
Lungs are very delicate organs and essential for breathing, thus beeping us alive. Smoking tobacco in the form of beedi, cigarette or cigar damages our lungs gradually and causes ill health. While smoking, smoke along with chemicals present in tobacco enters our body. These chemicals present in tobacco damages the lungs in many ways tike breathing becomes difficult causes lung cancer, heart diseases, etc. Smoking also affects people around smokers as they also inhale air containing tobacco. This is called passive smoking .
Refer to text on page 141.

Question 7.
Respiration can occur in two different manners. Briefly explain the process of aerobic respiration. How does it differ from anaerobic respiration?
Answer:
Types of Respiration
On the basis of the presence or absence of oxygen, respiration is classified into two types:
1. Aerobic Respiration: When breakdown of glucose occurs with the use of oxygen, it is called aerobic respiration. During aerobic respiration, glucose is completely broken down into carbon dioxide and water and energy is released. Aerobic respiration takes place in mitochondria. It can be shown by the following equation:

Aerobic respiration is seen in most of the organisms such as humans (man), dogs, cats, lions, elephants, cows, buffaloes, goats, snakes, earthworms, frogs, fishes, etc.

2. Anaerobic Respiration: When breakdown of glucose takes place without using oxygen, it is called anaerobic respiration. The glucose is not completely broken down into carbon dioxide and water. An intermediate compound is formed with the release of less amount of energy during this process. It can be shown as follows:

Yeasts such as Saccharomyces cereviseae and certain bacteria carry out anaerobic respiration. These organisms that carry out respiration in the absence of oxygen are called anaerobes.

Question 8.
Breathing rate of a person is not always constant. Give the reason for your answer.
Answer:
The number of times a person breathes in a minute is termed as breathing rate. An adult human being can inhale and exhale 15-18 times in a minute. It is the average breathing rate of an adult human being.

Breathing rate of a person is not always constant. It changes according to the oxygen requirement of the body. Breathing rate is somewhat faster in women than in men and in children it is higher (20-30 times/min) than adults. Breathing rate is slowest while sleeping (as less energy is required) while maximum during heavy exercise like running, weight lifting, etc. (much energy is required). Increased breathing rate provides greater amount of air entry into the lungs, hence blood can absorb oxygen at a faster rate. Faster breathing supplies more oxygen to the body cell for producing more energy, required for heavy exercises.

During heavy exercise the breathing rate can increase upto 25 times per minute. Because of this, food gets broken down at a faster rate and thus make us feel hungry.
When we feel drowsy, sleepy or tired, we yawn (i.e. open our mouth wide to take a long and deep breathe, of air), because our breathing rate slows down and body do not receives sufficient oxygen.

Question 9.
Whenever we feel drowsy or sleepy, we start yawning. Does yawning help us in anyway? [NCERT Exemplar; HOTS]
Answer:
When we feel drowsy, sleepy or tired, we yawn (i.e. open our mouth wide to take a long and deep breathe, of air), because our breathing rate slows down and body do not receives sufficient oxygen.

Question 10.
Respiration in fish is different from humans. Explain in brief how fishes can breathe through gills?
Answer:
Fishes are the aquatic animals that live in water. These have a special organ for breathing called gills. The oxygen dissolved in water enters through the gills. Gills are actually the projections of skin and have blood vessels for the exchange of respiratory gases. The fishes breathes by taking in water through its mouth and sending it over the gills. The oxygen dissolved in the water is extracted by the gills and the extracted oxygen is absorbed by the blood.

This oxygen is then carried to all the parts of fishes for respiration. The carbon dioxide produced during respiration is brought back by the blood into the gills and expelled into the surrounding water.

Question 11.
There are three animals named A, B and C. Among them A can stay on land as well as in water. When it stays at land is respire through lungs but when it goes into water, it respires through its moist skin. Animal B has specific organs to respire in the water which is not found in any other water animal. While animal C is a water animal which respires through nostrils and lungs. Now give the name of animal A, B and C. [HOTS]
Answer:
Animal A can live on land as well as in water and can respire through lungs as well as moist skin. The animal is frog.
Animal B lives in water and respires through a specific organ called gills. These are found in the tadpoles besides fishes. The animal B is a fish.
Animal C is also an aquatic animal which lives in sea water and respires through nostrils and lungs not by the gills. The animal is whale.

Question 12.
When breathe is released after holding it for few minutes. What happens and give reason for its occurrence?
Answer:
Releasing breathe after holding it for sometime results in rapid breathing. It occurs to maintain a healthy balance between intake of O₂ and release of carbon dioxide.

Question 13.
Observe the given figures carefully.and answer the following questions.
(a) The amount of CO₂ be the highest in which jar. Why?
(b) The amount of CO₂ be the lowest in which one and why?

Answer:
(a) The amount of CO₂ will be the highest in jar C. It is because the mice kept under the jar will breathe out CO2 continuously increasing its amount in the jar.
(b) The amount of CO₂ will be the lowest in jar A. It is because in jar A, CO₂ released during respiration is used by the plants, i.e. during the process of photosynthesis.

Question 14.
Whales and dolphins are seen many times releasing a fountain of water sometimes at the surface of water. Why do they do so?
Answer:
Sea animals like dolphins and whales live in water but unlike fishes, they do not possess gills for respiration. These possess nostrils which are called blow holes. There blow holes are located on the upper parts of their heads. These animals breathe in through their nostrils and lungs. Dolphins and whales comes to the surface of sea-water from time to time to breathe in air, sometimes whales release a function of water that moves upwards like a spray. This is because when a whale breathes air out of its blow hole it appears as a spray or misp, also called as spont. It can be seen from many miles away. Blow holes are surrounded by muscles that keep the holes closed when the whales or dolphins are under water and opens it when the animal is at the surface and needs to breathe.

Human cannot survive under water because they do not possess any gills to make use of oxygen dissolved in water for breathing. When we go under water we have to take oxygen gas cylinders for breathing.

Question 15.
Observe the given diagram of human respiratory system. List the organs from (A) to (G).

Answer:
The human respiratory system have following organs:
A-Ribs
B-Trachea
C-Pharynx
D-Diaphragm
E-Lungs
F-Nasal passage
G-Oral cavity

Question 16.
A girl was suffering from cold and was sneezing continuously. She joined her family at dinner and suddenly started sneezing without covering her nose, thus sending particles all over the place. On realising her mistake, said sorry and next time covered her nose.
(a) During sneezing, what are the precautionary steps to be followed?
(b) Can infections be passed from one person to another via sneezing?
(c) Is sneezing a respiration process?
(d) What values do we pick from this situation? (Value Based Question]
Answer:
(a) When sneezing, you should cover your nose so that the particles expelled by you would not be inhaled by others.
(b) Yes.
(c) No, it is process to remove/clear the particles harmful for us resulting in clean, fresh air to enter the lungs.
(d) Cleanliness and hygiene maintenance.

Respiration in Organisms Class 7 Science Extra Questions Long Answer Type Questions

Question 1.
A food stall owner was preparing dough for making bhaturas. He added a pinch of yeast and sugar to the dough and left it in a warm place. After few hours, the dough had risen. There was a sour smell too.
(a) Why did the dough rise?
(b) Why did the dough smell sour?
(c) Why was sugar added to the dough?
(d) What would have happened if the dough was kept in the refrigerator, soon after it was prepared?
Answer:
(a) The dough rises due to the release of carbon dioxide during anaerobic respiration by yeast cell.
(b) Yeast, during anaerobic respiration also produces alcohol which results in the sour smell of dough.
(c) Sugar is added into the dough, because it acts as a food for yeast. Yeast upon incomplete breakdown of sugar or food produces CO₂, alcohol and energy (in less amount).
(d) If the dough is kept in the refrigerators after it was prepared, then dough will neither raise nor become sour. Yeast requires high temperature to grow, multiply and to respire. At low temperature, the yeast will not respire to produce the byproducts of anaerobic respiration.

Question 2.
(a) Plants lack a specialised respiratory system. How do they carry out respiratory process? Explain.
(b) The plant roots being underground respire by using which mechanism?
Answer:
(a) The plants do not possess any respiratory system still plants respire. The various parts of the plants like leaves, roots, etc., carry out respiration independently.
These parts take in oxygen from air in different manner and utilise it to obtain energy and give out C02. The leaves of plants possess tiny pores on their surface which is called as stomata. The gaseous exchange during respiration takes place through their stomata.

(b) Roots of the plants respire under the ground. Root cells get oxygen from the air present in the space between the soil particles.
There are several root hairs present on the roots of a plant.
The oxygen from the air (between soil particle) diffuses into root hair and reaches to the cells of the roots. This oxygen is utilised for respiration.

Question 3.
Paheli participated in a 400 m race competition held at her school and won the race. When she came home she had mixed feelings of joy and pain as she had cramps in her leg muscles. After a massage, she was relieved of the pain. Answer the following questions related to the situation.
(a) What can be the possible reasons for the pain in her legs?
(b) Why did she fell comfortable after a massage? [NCERT Exemplar; HOTS]
Answer:
(a) Paheli had cramps in her leg muscles after running. She felt pain in her legs because of accumulation of lactic acid in the leg muscles. Lactic acid is formed due to anaerobic respiration in the muscle cells after heavy exercise or running. After heavy exercise, we require large amount of energy.
To produce more energy to meet the oxygen requirement of muscles, muscle cells perform anaerobic respiration for a short duration.
Lactic acid is formed due to partial breakup of glucose. It gets accumulated in the muscle cells and causes pain and muscle cramps.

(b) The massage or hot water bath gives the relief from muscle cramp or pain, because it improves the circulation of blood leading to increase supply of oxygen to the muscle cells. It helps in complete breakdown of lactic acid into carbon dioxide and water.

Question 4.
It is not wise to sleep under a tree during night. Why?
Answer:
During day, plants photosynthesise in the presence of sunlight and uses CO₂ produced during respiration. During this process O₂ is released as a byproduct and a balance between O₂ and CO₂ is maintained in the atmosphere.

But in the night, plants do not photosynthesise. Plants are unable to use CO₂ during night and produces CO₂ and takes O₂ during respiration.
This leads to the increase in the proportion of CO₂ in the air.
So, if one sleeps under a tree at night, he will have problems in breathing as the amount of CO₂ in the air around will certainly be more than oxygen. Therefore, it is not advisable to sleep under trees during night because the person will suffer from suffocation and feel excess weight on chest.

Question 5.
Observe the figures carefully and answer the following questions.

(a) Which process is being tested in the activity?
(b) What is the result of the activity? Give reasons. [NCERT Exemplar]
Answer:
(a) Exhalation process of respiration is being tested in the activity.
(b) The lime water in test tube B turns milky but water in test tube A remains unchanged. Because CO₂ is present in the exhaled air, it mixes with lime water in test tube B and turns it milky.

Question 6.
(a) Respiratory process occurs in two phases, what are those two major steps of respiration? Describe each one.
(b) Define the term breathing rate.
Answer:
(a) Respiration is the process of breakdown of food to produce energy for performing various functions. It involves two major steps:

Inhalation is the process of taking in of air which is rich in oxygen, inside our body.
Exhalation is the process of giving out of air which is rich in carbon dioxide from our body to the external environment.

(b) The number of times a person breathes, in a minute is called as breathing rate.
An adult human being can inhale or exhale 15-18 times in a minute. It is the average breathing rate of an adult human being. Breathing rate is not constant always.

Question 7.
Observe the given figures as A and B and answer the following questions.

(a) Among both figures identify which A or B indicates the process of inhalation and which shows the process of exhalation?
(b) In the figure label the arrows and indicate the direction of

movement of air
movement of diaphragm
movement of ribs [NCERT Exemplar]

Answer:
(a) Figure A indicates inhalation and figure B indicates exhalation.
(b) Movement of air, diaphragm and ribs are indicated in below figure:

Question 8.
List some animals around you. Now group them as follows:
(a) Animals that can breathe only through skin.
(b) The animal that can breathe through skin as well as through lungs.
(c) The animal that can breathe through lungs.
(d) Animals that can breathe through gills.
(e) Animals that can breathe through spiracle and tracheae? [HOTS]
Answer:
(a) Animals that can breathe only through skin are earthworm and leech.
(b) Animals that can breathe through skin as well as through lungs are frogs.
(c) Animals that can breathe through lungs are buffaloes, human, and dolphins.
(d) Animals that can breathe through gills are tadpole and fish.
(e) Animals that can breathe through spiracles and tracheae are grasshopper, cockroaches, ants, housefly and mosquito.

Question 9.
Palak wants to be a great cyclist. She cycles daily for about 2 hours followed by some exercises. Today, she thought she will cycle for longer and managed it for 41/2 hours. Now she is feeling cramped up and her breathing is disturbed. Her mother took her to hospital where the doctor examined and told her not to push herself more than necessary. Palak understood and promised herself to move show and steadily.
(a) Why did Palak had cramps in her legs?
(b) Is breathing rate also affected after doing long hour of exercise. Why?
(c) When there is not enough oxygen supply,
what happens to body and process of respiration? What values you learn from this? [Value Based Question]
Answer:
(a) Due to extensive exercise, formation of lactic acid occurred as muscles starts to respire anaerobically.
(b) Yes, breathing rate will be faster. Normally we are breathing at a slower rate but during physical activities, to make sufficient amount of O₂ reaching cells we breathe faster.
(c) The body starts respiring anaerobically in the absence of sufficient oxygen. Glucose is partially broken into lactic acid which causes body cramps.
Values learned – We should not force ourselves exercise but not over burn yourself discipline.

Question 10.
A person put some warm water in an aquarium having fish during winter season. He thought that fish will be more comfortable in luke warm water than cold water. But he observed that fishes in the aquarium died. Why the fishes died in warm water? [HOTS]
Answer:
The fishes have special type of organs for respiration called gills. These gills absorbs oxygen dissolved in water and through blood vessels, this oxygen is passed to all the parts of the body. The amount of dissolved oxygen is comparatively less in water than the amount of oxygen in air.
Therefore, the rate of breathing is also high in aquatic animals.
If we add warm water, to the aquarium the dissolved oxygen will dissociate and move into the atmosphere again, leaving the least percentage of oxygen into the water (as it is known that the solubility of gases in water goes down as the temperature rises). Therefore, fishes will have difficulty in breathing in the absence of oxygen and will die.

Question 11.
A group of people were smoking cigarettes in a restaurant. The atmosphere was full of smoke. An old man sitting next to the group asked them to stop smoking while sitting in the premise or move out. They agreed to do so and promised not to repeat then mistake.
Answer the following questions.
(a) Write any three hazards of smoking.
(b) Can smoking also affect the person who does not smoke?
(c) Do you support the group’s decision to not smoke in public or indiviually. What values do we understand
from here. [Value Based Question]
Answer:
(a) Smoking is very injurious for the respiratory system. It harms lungs.

It causes blockage in respiratory tract.
It leads to lung cancer.
It can cause disease like asthma and heart diseases.

(b) Yes, smoking affects people who are passive smokers, i.e. those present nearby smokers.
(c) Yes, the people should bot smoke in public areas as it can cause discomfort to others.
The values we understand are obedience, respect elders and healthy habits.

Rohit0 comments

CHAPTER – 9 Soil | CLASS 7TH | NCERT SCIENCE IMPORTANT QUESTIONS & MCQS | EDUGROWN

SCIENCE IMPORTANT QUESTIONS & MCQS FOR CLASS 7th

Chapter - 9 Soil

MCQs

Question 1.
Which one of the following is a step in the formation of soil?
(a) Earthquakes or volcanic eruptions
(b) Weathering of rocks
(c) Addition of humus
(d) All are involved in the formation of soil

Answer

Answer: (d) All are involved in the formation of soil

Question 2.
In which horizon of soil minerals are found?
(a) A
(b) B
(c) C
(d) None of these

Answer

Answer: (b) B

Question 3.
Which physical property of soil is important to us?
(a) Texture
(b) Water holding capacity
(c) Both of these
(d) None of these

Answer

Answer: (c) Both of these

Question 4.
Which of the following type of soil will form a colloidal solution when suspended in water?
(a) Clay
(b) Silt
(c) Sand
(d) Gravel

Answer

Answer: (a) Clay

Question 5.
Which factor influences soil formation?
(a) Climate
(b) Vegetation
(c) Parent rock
(d) All of these

Answer

Answer: (d) All of these

Question 6.
The proportion of sand, silt and clay in a soil sample determines
(a) structure
(b) texture
(c) nutrient potential
(d) fertility level

Answer

Answer: (b) texture

Question 7.
The microorganisms present in the soil require moisture (water) and nutrients for growth and survival. Choose from the options below the habitat (place) where the soil has plenty of water and nutrients.
(a) Desert
(b) Forest
(c) Open field
(d) Cricket ground

Answer

Answer: (b) Forest

Question 8.
Availability of water and minerals in the soil for maximum absorption by roots is in the:
(a) B-horizon
(b) C-horizon
(c) A-horizon
(d) Surface of soil

Answer

Answer: (c) A-horizon

Question 9.
Soil conservation measures are mainly aimed at protecting which of the following?
(a) Plants
(b) Topsoil
(c) Sub soil
(d) Soil organisms

Answer

Answer: (b) Topsoil
Soil conservation measures mainly aim at protecting topsoil, which is rich in humus and nutrients making it fertile to grow plants.

Question 10.
Read the following statements with reference to soil:
(i) Weathering is a very fast process of soil formation.
(ii) Percolation of water is faster in sandy soils.
(iii) Loamy soil contains only sand and clay.
(iv) Top soil contains the maximum amount of humus.
Choose the correct statements from the above.
(a) (ii) and (iv)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (i) and (ii)

Answer

Answer: (a) (ii) and (iv)

Match the following:

Column A	Column B
(i) Silt	(a) Particle size less than 0.005 mm
(ii) Gravel	(b) Particle size between 0.005 and 0.05 mm
(iii) Sand	(c) Particle size between 0.05 and 2.00 mm
(iv) Clay	(d) Particle size greater than 2.00 mm
(v) Wheat, gram and paddy	(e) Sandy loam soil
(vi) Cotton	(f) Clayey soil
(vii) Pots, toys and statues	(g) Clay and loam soil

Answer

Answer:

Column A	Column B
(i) Silt	(b) Particle size between 0.005 and 0.05 mm
(ii) Gravel	(d) Particle size greater than 2.00 mm
(iii) Sand	(c) Particle size between 0.05 and 2.00 mm
(iv) Clay	(a) Particle size less than 0.005 mm
(v) Wheat, gram and paddy	(g) Clay and loam soil
(vi) Cotton	(e) Sandy loam soil
(vii) Pots, toys and statues	(f) Clayey soil

Fill in the blanks:

1. Soil is formed by ……………… of rocks.

Answer

Answer: weathering

2. A dark soil is usually rich in ………………

Answer

Answer: organic matter/humus

3. The physiochemically active portion of soil is ………………

Answer

Answer: top soil

4. Soil erosion can be stopped by ………………

Answer

Answer: plantation

5. Erosion involves movement of ……………… from one place to other.

Answer

Answer: soil

6. Soil is of different types: clayey, loamy and ………………

Answer

Answer: sandy

7. ……………… is a section through different layers of the soil.

Answer

Answer: Soil profile

8. ……………… soil is used to make pots, toys and statues.

Answer

Answer: Clayey

Choose the true and false statements from the following:

1. Upper portion of soil always contains air.

Answer

Answer: True

2. Percolation rate of water is highest in the clayey soil and least in the sandy soil.

Answer

Answer: False

3. Clay and loam are suitable for growing wheat, gram and paddy.

Answer

Answer: True

4. Cotton is grown in sandy loam soil.

Answer

Answer: True

5. Capacity to hold water is more in sandy soil than clayey soil.

Answer

Answer: False

6. Clayey soil is used for making pots, toys and statues.

Answer

Answer: True

7. Erosion of soil is more severe in areas of high vegetation.

Answer

Answer: False

8. Polythene bags and plastics pollute the soil.

Answer

Answer: True

Imoprtant Questions

Question 1.
In how many groups the soil has been categorised? Name them.
Answer:
The soil has been categorised into four major groups, i.e.

clay
silt
sand
gravel

Question 2.
Which soil is considered to be the most fertile and used for growing crops?
Answer:
Loamy soil is the most fertile soil and used for growing crops.

Question 3.
Which type of soil absorbs more water but allows less wateMo percolate?
Answer:
Clayey soil absorbs more water but allows less water to percolate

Question 4.
Give the formula to calculate the absorption percentage.
Answer:
The absorption percentage of water can be calculated by the formula given below
Percentage of water absorb = Amount of water absorbed (in mL) Amount of soil (in gm) ×100

Question 5.
When we add some dry soil to the water in a glass and stir it, bubbles are observed from the soil. What causes these bubbles to raise? [HOTS]
Answer:
When dry soil is added in the water in a glass and stir it, bubbles appear. These bubbles are caused due to the air present in between the soil particles.

Question 6.
What is weathering?
Answer:
Weathering is a natural process by which huge rock is broken down into tiny particles but at a very slow rate.

Question 7.
There is shimmering of air just above the soil during hot summer day. What does the term shimmering indicate? [HOTS]
Answer:
The term shimmering means that the air shines with a slightly shaking light.

Question 8.
Draw a diagram to show the different layers of soil.
Answer:
Soil Class 7 Extra Questions Science Chapter 9 1

Question 9.
Name two soil types used for cultivation.
Answer:
Clayey soil and loamy soil are rich in humus and are suitable for growing plants like wheat and gram.

Question 10.
Soil has particles of different sizes. Arrange the words given below in decreasing order of their particle size. Rock, clay, sand, gravel, silt [NCERT Exemplar]
Answer:
The soil particles with the decreasing order of their particle sizes can be shown as
Rock > gravel > sand > silt > clay

Question 11.
There are two components of soil one that comes from living thing and other from non-living thing. What are these two components?
Answer:
The two major components of soil are weathered rock particles, i.e. non-living components and humus that consists of living organisms like fungi, bacteria, worm, insects, etc.

Question 12.
It is necessary to ban the use of polythene bags and plastics. Do you agree? If yes, why? [HOTS]
Answer:
Polythene bags and plastics pollute the soil as they kill the organisms living in the soil.
That’s why, it is necessary to ban the use of polythene bags and plastics.

Question 13.
List the substances which pollute the soil.
Answer:
The substances which pollute the soil are polythene bags, plastics, waste products, chemicals, pesticides, etc.

Question 14.
A special kind of soil is used for making matkas and surahis. Name it. [HOTS]
Answer:
Clayey soil is used to make matkas and surahis.

Question 15.
Explain the term humus that is generally found in the uppermost layer of soil.
Answer:
The rotting dead matter in the soil is called humus.

Question 16.
Can we make toys with the soil obtained from a field? Explain.
Answer:
No, soil from a field cannot be used to make toys. In order to make toys, the soil should be clayey.

Question 17.
The percolation rate varies from soil to other soil. Which soil would have the highest and least percolation rate?
Answer:
Percolation rate of water is highest in the sandy soil, while the lowest in the clayey soil.

Question 18.
How can a farmer convert acidic soil into neutral soil? [NCERT Exemplar]
Answer:
The farmer can convert acidic soil into neutral soil by adding a small quantity of quicklime or slaked lime solution to the soil.

Question 19.
Do all types of soil absorb water to the same extent? Give reason for your answer.
Answer:
No, it is because different types of soil has different absorbing capacity of water.

Question 20.
For planting rice, which kind of soil would be most suitable?
Answer:
For planting paddy (rice), clayey soil that is rich in organic matter and have a good water retaining capacity is ideal.

Soil Class 7 Science Extra Questions Short Answer Type Questions

Question 1.
The soil is said to be inseparable part of our life. Why?
Answer:
Soil is one of the most important natural resources. It is the uppermost layer of earth’s crust which is blackish-brown in colour. Major functions of the soil are:

It supports plant growth by holding the roots firmly and supplying water and nutrients to the plants.
It acts as a natural habitat for many organisms like earthworm, fungi, bacteria, ants, etc.
It is also essential for agriculture which provides us food, clothing and shelter for all.
It supplies water and nutrients to plants.

Therefore, we can say that the soil is inseparable part of our life.

Question 2.
Suppose certain sample takes 120 min for 960 mL water to percolate into the soil. Calculate the rate of percolation of water.
Answer:
Given, amount of water = 960 mL
Time taken to percolate =120 min
The rate of percolation will be
= Amount of water (in mL) Percolation time (in min) =960mL120min=8mL/min
Percolation rate = 8 mL/min

Question 3.
Locate the following zones given as boxed items in figure which shows a diagram of soil profile.
Topsoil, subsoil, bedrock [NCERT Exemplar]
Soil Class 7 Extra Questions Science Chapter 9 2
Answer:
It is the uppermost layer of soil and is usually dark in colour because of the presence of minerals and humus in it. It provides the nutrients in plants, since the roots of most plants are confined to this layer. Humus is the dark brown coloured layer which consists of dead, rotting remains of plants and animals.
Soil Class 7 Extra Questions Science Chapter 9 1
This layer of soil lies just below the topsoil. It is made up of slightly bigger rock particles than that of the topsoil. It does not have much humus and is lighter in colour than topsoil. It is somewhat harder and more compact than the topsoil. This layer is less fertile than topsoil and contains few living organisms. Subsoil is rich in minerals and iron oxides.

Below the C-horizon unweathered solid rock is found which is called as bedrock. It is non-porous and can produce the soil over a long period of time. Rainwater gets collected over it to form water table.

Question 4.
A student visits two types of field and observes that soil from field A has high percolation rate of water, while soil from field B has low percolation rate. In field B, paddy crop was grown while in field A, there was no standing crop. Name two types of soil present in two fields. [HOTS]
Answer:
Soil in field A is sandy soil while in field B soil is clayey soil which has low percolation rate and water-logging is seen. Since, paddy requires lot of standing water, therefore it is grown in field B.

Question 5.
Describe how clayey soil is useful for crops?
Answer:
Clayey soil is useful for the crops because

it has good water retaining capacity.
it is rich in humus.
it is fertile in nature.

Crops like wheat and rice can be easily grown in clayey soil.

Question 6.
Read the following statements and give the appropriate terms for each of them.
(a) The process of breakdown of rocks by the action of wind, water, sunlight.
(b) Removal of topsoil during heavy rains or strong winds.
(c) Accumulation of wastes in the soil generated by human activity which alter the features of soil.
(d) The process of movement of water into deeper layers of soil. [NCERT Exemplar]
Answer:
The terms for the above described statements are as follows
(a) Weathering
(b) Soil erosion
(c) Soil pollution
(d) Percolation

Question 7.
Describe the different type of soil.
Answer:
There are three different types of soil

Sandy soil containing sand particles in them.
Clayey soil contains clay particles with small amount of humus in it. It is a fertile soil.
Loamy soil is a mixture of sand, clay silt and humus. It is a fertile soil

Question 8.
Rajasthan is a desert state in India. Once while travelling to Rajasthan by train, Boojho observed several streams and rivulets of rainwater during the journey but to his surprise, he did not see streams of water in the desert region even during rains. Help Boojho to find a suitable explanation for this. [NCERT Exemplar; HOTS]
Answer:
Deserts are made up of sand, thus when the rainwater falls on land, it percolates immediately downwards in the spaces between sand particles. So, the streams of water in desert region are not visible even during rainy season.

Question 9.
A man digging a pit found that he could dig with ease initially but digging became difficult as he went deeper. He could not big beyond a depth 5 feet. Provide a suitable scientific explanations. [NCERT Exemplar; HOTS]
Answer:
The man digging a pit could dig with ease initially because of the presence of topsoil and subsoil (mainly comprising of humus and nutrients). But as he digs deeper, he finds it difficult to dig beyond a depth of 5 feet as lower layers are made up of small partially weathered rocks with cracks, crevices and with bedrock which make it hard to dig.

Question 10.
Continuously water-logged soils are disadvantageous for plant growth. Why? [NCERT Exemplar]
Answer:
Roots although underground possesses living cells that require oxygen for respiration and production of energy. They absorb oxygen that is present in the spaces between soil particles. But in water-logged soils, water occupies spaces between soil particles and pushes the oxygen out into the atmosphere. Thus, roots are deprived of oxygen and this affects the plant growth.

Question 11.
Is it a good practice to remove grass and small plants that are growing in an open, unused field? Give reason to support your answer. [NCERT Exemplar; HOTS]
Answer:
No, it is not a good practice to remove grass and small plants growing in an open, unused field because the plants cover the soil surface. Their roots bind the soil particles, holding and adhering them in place. It helps in preventing the topsoil from being washed off during heavy rain, floods and winds.
In this way, soil erosion is prevented and topsoil layer is preserved for growing more plants.

Question 12.
Observe the following figure and answer the following questions.
Soil Class 7 Extra Questions Science Chapter 9 3
(a) Which is the heaviest rock material?
(b) Which is the lightest soil component?
(c) Why different layers of soil component are formed?
Answer:
(a) Gravel is the heaviest rock material.
(b) Humus is the lightest soil component which floats on the water surface.
(c) The soil component forms various layer one above the other according to the size of soil particle.

Question 13.
During the summer vacations, Gaurav visited his native village. He observed that farmers were using pesticides in their field. He contacted the village head and explained him the effects of such substances in causing soil pollution. Next day, the village head called a meeting of all the villagers and convinced the villagers not to use chemicals and pesticides.
(a) Why is there a ban to demand the polythene bags and plastics.
(b) List some substances which pollute the soil.
(c) What are the values shown by Gaurav? [Value Based Question]
Answer:
(a) It is because these substances pollute the soil. They also kill the organisms living in the soil.
(b) Substances which pollute the soil are a number of waste products, chemicals, pesticides, polythene bags and plastics.
(c) Alertness, responsibility and ecofriendly nature.

Question 14.
Write the difference between rate of percolation and the amount of water retained.
Answer:
Percolation property of any material is linked to its porosity. Different soils have different porosity.
Therefore, water percolates differently through different soil.
Percolation rate of water in the soil = Volume of water percolated Time taken for percolation
Whereas water retaining capacity of a soil is described in terms of the amount of water absorbed by a particular type of soil. High water retaining capacity means higer water absorption.

Question 15.
Why is soil erosion relatively less in dense forests as compared to barren, open fields? [NCERT Exemplar; HOTS]
Answer:
In dense forests, the tree cover (canopy) prevents rainwater from directly falling on the ground/soil. Also roots of the vegetation bind the soil particles and hold them together. As a result, soil erosion is minimised.
But in barren, open fields, the soil is exposed to the falling rain. The soil particles become loose due to the impact of raindrops and the flow of water carries them away. The flowing water further erodes the soil surface aggravating erosion.

Question 16.
Gardeners gently dig up the soil around the roots of garden herbs (plants) frequently. Give reasons. [NCERT Exemplar. HOTS]
Answer:
A gardener often gently digs up the soil around the roots of garden plants or herbs for following reasons

It enables easy root growth.
For easier percolation of water.
For aerating the soil enabling air to get into deeper layers of soil.
For removing the weeds.

Soil Class 7 Science Extra Questions Long Answer Type Questions

Question 1.
Explain through an activity that soil has moisture in it.
Answer:
Take a plastic funnel and a filter paper. Fold the filter paper and place it in a plastic funnel. Now keep the funnel (with filter paper) in a beaker. Take some dry powdered soil and weigh it on a balance.
Note the mass of the soil taken. Now pour this weighed soil into the filter paper fixed in a funnel.
Soil Class 7 Extra Questions Science Chapter 9 4
Take a measuring cylinder and fill it with water. Note the initial volume of water in the measuring cylinder. Take water from measuring cylinder with the help of a dropper and pour it drop by drop on the soil kept in the funnel. Be careful that water should not fall at one spot on the soil but should be poured uniformly all over the soil. Keep pouring water till it starts dripping from the lower end of the funnel.
Dripping of water from funnel shows that the soil taken on the filter paper has absorbed the maximum amount of water. Note the final volume of water that is left unused in the measuring cylinder.

By substracting the amount of water left in the measuring cylinder from the amount of initial volume of water taken in the measuring cylinder. We will get the volume of water absorbed by the soil which was taken on filter paper in the funnel. The difference in two reading gives the amount of water retained by the soil. The calculation can be done as follows:
Suppose, the mass of the soil taken = 50 g
Let the initial volume of water U = 100 mL
and final volume of water V = 60 mL
Therefore, the volume of water absorbed by the soil = (U- V) mL = (100 – 60)mL = 40 mL
and weight of the water absorbed by the soil = (U – V)Q = (100 – 60) g = 40 g
Therefore, the percentage of water absorbed = =(U−V50×100)=4050×100=80%
When we perform this activity with different soil samples, we will see that.

Sandy soil will absorb less water and allows more water to percolate.
Clayey soil will absorb more water but allow less water to percolate.
Sandy soil will absorb less water than clayey soil because of the large spaces between the soil particles. The area where, there is a lot of clay in the soil, stagnant water collects above the soil whenever it rains.

Question 2.
Design an activity to show the soil erosion on a barren land.
Answer:
Strong wind and rain can cause soil erosion from the barren land. This can be shown by performing an activity.
Take a wooden block and place some soil or sand on it. Keep an ice-cube tray at one end of the wooden black. Take a small battery-operated fan or hair dryer and hold it at the other end of the black near sand so that it blows the sand into the tray.

We will observe that when the fan blows it causes sand or soil particles to move and these get land in the various compartment of the ice-cube tray. This activity shows that the wind blows the soil on a barren land and may cause soil erosion.
Soil Class 7 Extra Questions Science Chapter 9 5

Question 3.
The contamination of soil with waste materials causes soil pollution. Does the use of pesticides in agriculture also contribute to the soil pollution? Explain.
Answer:
The contamination of soil with waste materials especially used polythene bags and plastics, pesticides, fertilisers, acid rain industrial chemical wastes, etc., is called soil pollution.

Pesticides are the poisonous chemical substances which are sprayed on standing crops to save them from the harmful insects and diseases. Some of these pesticides also mix up with the soil in the fields and pollute it. The grains, fruits and vegetables grown in this polluted soil contain pesticides. When we eat such contaminated grains, fruits or vegetables, the pesticides present in them damage our health also.

Question 4.
A soil sample was taken from an agricultural land and was weighed. The mass of the soil was found to be 50 g. 100 mL of water was taken in a measuring cylinder and added into the soil sample. The soil absorbed 80 mL of water and rest left in the measuring cylinder. Calculate the absorption rate of water by the soil. [HOTS]
Answer:
The absorption rate of water by soil can be calculated by the formula as follows:
Soil Class 7 Extra Questions Science Chapter 9 6
40% of the water has been absorbed by the soil.

Question 5.
(a) Soil has various important component. Write them.
(b) Arrange the following rock particles which occur in soil in the increasing order. Silt, clay, gravel, sand.
(c) Observe the following figure. What does this figure show?
Soil Class 7 Extra Questions Science Chapter 9 7
Answer:
(a) The various important component of soil are air, water, rock particles, minerals, humus and living organisms like bacteria, fungi, worms (earthworm), rodents, insects (ant and beetle), etc.
(b) The increasing order of rock particles are
Clay → Silt → Sand → Gravel
(c) The figure shows waste material like polythene bags, plastics, glass and metal objects are dumped which causes soil pollution.

Question 6.
In towns and cities, generally, the borewells have to be dug very deep to get water as compared to borewells dug in villages. Give suitable reasons. [NCERT Exemplar; HOTS]
Answer:
The borewells have to be dug very deep to get water as compared to those in villages because

excessive use of water depletes the groundwater.
towns and cities have asphalted roads and vast areas of soil are concreted. As a result, rainwater cannot percolate to recharge groundwater and the groundwater level further decreases. Villages have larger areas of open soil surface and fewer asphalted roads and concrete surfaces.

Thus, larger soil surface area is available for rainwater to percolate into the soil easily and recharge the groundwater. As a result, even shallow borewells yield water.

Question 7.
Soil erosion does not occur easily where the land is covered by vegetation. Do you agree? Explain.
Answer:
Yes, soil erosion does not occur easily where the land is covered by vegetation (trees and other plants). It occurs easily in those areas of land which are not covered by vegetation (trees and other plants) or have very little vegetation. If there is vegetation on land,

then the roots of vegetation growing in the soil bind the particles of topsoil firmly. Due to this, the blowing wind and flowing rainwater are not able to carry away topsoil and hence soil erosion does not occur.
then much of the falling rain hits the trees and plants before it hits the soil. In this way, the cover of vegetation softens the effect of heavy rains on the soil.

Question 8.
The raw and baked soil differs from each other. How they are different? How can you prepare matkas from soil? [HOTS]
Answer:
Raw soil differs from baked soil. The raw soil is white or dull blackish coloured soil. It contains water and air in it and can be moulded.

Baked soil is the heated raw soil which lost its water molecule due to heating and becomes red. Once the soil gets heated, it cannot be moulded into other form. Clay soil is used for making matkas, toys, pots, etc. The soil is kneaded along with horse dung to make best quality of raw clay soil. This kneaded soil is then placed on the wheel and appropriate shape is given. The final shape of the material is given with hands. The pots and matkas are then kept for drying for three days. These items are baked at high temperature after drying in air and then coloured.

Question 9.
During a field trip, some students visited an agricultural farm and saw a few birds eating earthworms. They enjoyed the scene and then they also started picking and killing the earthworms for pleasure. Seeing the crowd of students in a corner, the teacher rushed to them to see the matter and objected to their action. Anshul, one of the student asked the reason.
Teacher smiled and explained him that an earthworm living in the soil is very beneficial for farmers. Anshul wondered whether there were other organisms also in the soil. The teacher appreciated him and explained.
(a) Mention the importance of earthworm.
(b) List some organisms living in soil.
(c) What are the values shown by Anshul? [Value Based Question]
Answer:
(a) An earthworm helps in making the rich humus in soil.
(b) Ant, earthworm, termites, milipede, centipede, etc.
(c) Curiosity to learn and scientific attitude.

Question 10.
A soil sample having mass of 200 g was taken from garden.This soil was dried completely in the oven and again weight. The weight of the soil now was found to be 170 g. Calculate the percentage of water or moisture content present in the sample soil. [HOTS]
Answer:
The moisture content of the soil can be calculated by the formula as follows:
= Mass of water in soil Original mass of soil ×100
Given, Original mass of soil = 200 g
Mass of soil after drying =170 g
Then mass of water in soil will
= 200 – 170 = 30 g
The percentage of water in soil will be
30g200g×100=15%

Rohit0 comments

CHAPTER – 8 Winds, Storms and Cyclones | CLASS 7TH | NCERT SCIENCE IMPORTANT QUESTIONS & MCQS | EDUGROWN

SCIENCE IMPORTANT QUESTIONS & MCQS FOR CLASS 7th

Chapter - 8 Winds, Storms and Cyclones

Question 1.
In which year was Orissa hit by a cyclone?
(a) 1999
(b) 2000
(c) 2001
(d) 2004

Answer

Answer: (a) 1999

Question 2.
Leaves of trees, banner or flags flutter when wind is blowing. Why?
(a) Air occupies space
(b) Air is a mixture of gases
(c) Air exerts pressure
(d) Air is colourless

Answer

Answer: (c) Air exerts pressure

Question 3.
When we blow over a paper strip it goes upward as shown in the figure given below. why?

(a) Blowing over the paper reduces the air pressure above the strip
(b) Blowing over the paper increases the air pressure above the strip
(c) None of these is a correct reason
(d) The strip will not go upward at all

Answer

Answer: (a) Blowing over the paper reduces the air pressure above the strip

Question 4.
Following are precautions one must take in case a storm is accompanied by lightning.
(i) Do not take shelter under a tree.
(ii) Do not take shelter under an umbrella with a metallic end.
(iii) Do not take shelter in open garages, storage sheds, etc.
(iv) Do not take shelter in a bus in the open.
Which one of these is not correct?
(a) (i)
(b) (ii)
(c) (iii)
(d) (iv)

Answer

Answer: (d) (iv)

Question 5.
Which of the following places is most likely to be affected by a cyclone?
(a) Mumbai
(b) Puri
(c) Goa
(d) Porbandar

Answer

Answer: (b) Puri

Question 6.
A fire alarm usually detects smoke in case of fire. Where should such an alarm be placed in a room? (NCERT Exemplar)
(a) Near the door
(b) On the floor
(c) On any wall
(d) On the ceiling

Answer

Answer: (d) On the ceiling

Question 7.
The winds from oceans carry water and bring rain. These winds are called
(a) typhoon
(b) monsoon
(c) cyclone
(d) none of these

Answer

Answer: (b) monsoon

Question 8.
What is a cyclone?
(a) Winds from the oceans carrying water
(b) Very low pressure system with very high speed winds revolving around it
(c) Dark funnel shaped cloud that reaches from the sky to the ground
(d) None of these

Answer

Answer: (b) Very low pressure system with very high speed winds revolving around it

Question 9.
Pick the odd one out
(a) Cyclone
(b) Hurricane
(c) Monsoon
(d) Typhoon

Answer

Answer: (c) Monsoon

Question 10.
A cyclone warning can be issued
(a) 48 hours in advance
(b) 12 hours in advance
(c) 6 hours in advance
(d) 24 hours in advance

Answer

Answer: (d) 24 hours in advance

Match the following:

Column A	Column B
(i) Wind	(a) Dark funnel shaped cloud
(ii) Monsoon	(b) Very low pressure system with very high speed winds revolving around it
(iii) Thunderstorm	(c) measures the speed of wind
(iv) Cyclone	(d) develops in India very frequently
(v) Tornado	(e) Moving air
(vi) Anemometer	(f) Winds carrying water

Answer

Answer:

Column A	Column B
(i) Wind	(e) Moving air
(ii) Monsoon	(f) Winds carrying water
(iii) Thunderstorm	(d) develops in India very frequently
(iv) Cyclone	(b) Very low pressure system with very high speed winds revolving around it
(v) Tornado	(a) Dark funnel shaped cloud
(vi) Anemometer	(c) measures the speed of wind

Fill in the blanks:

1. Moving ………………… is called a wind.

Answer

Answer: air

2. Air exerts …………………

Answer

Answer: pressure

3. Increased wind speed is accompanied by ………………… air pressure.

Answer

Answer: reduced

4. The warm air is ………………… than cold air.

Answer

Answer: lighter

5. Wind currents are generated due to ………………… heating on the earth.

Answer

Answer: uneven

6. Very pressure system with very ………………… speed winds revolving around it is called a cyclone.

Answer

Answer: low,high

7. A dark funnel shaped ………………… that reaches from the sky to the ground is called a tornado.

Answer

8. ………………… and ………………… have made possible to issue a cyclone alert, i.e., 48 hours in advance.

Answer

Answer: Satellites, radars

Choose the true and false statements from the following:

1. Air around us exerts pressure.

Answer

Answer: True

2. Air contracts on heating and expands on cooling.

Answer

Answer: False

3. As cool air rises air pressure at that place is reduced and the warmer air moves to that place.

Answer

Answer: False

4. Winds carrying water vapours bring rains.

Answer

Answer: True

5. High speed winds and air pressure differences can cause cyclones.

Answer

Answer: True

6. Cyclones are beneficials to the people living in coastal areas.

Answer

Answer: False

7. Tornadoes are very frequent in our country.

Answer

Answer: False

8. It has become easier to monitor cyclones with the help of advanced technology like satellites and radars.

Answer

Answer: True

Question 1.
Why is Chandigarh unlikely to be affected by a cyclone? [NCERT Exemplar]
Answer:
Chandigarh is unlikely to be affected by a cyclone because it is not near to the sea or an ocean.

Question 2.
Discuss the major cause of winds.
Answer:
Wind currents are generated due to uneven heating on the earth. It may be between equator and pole and between land and water.

Question 3.
Name the ocean which is mainly responsible to bring rain bearing monsoon winds to Kerala coast in June every year. [NCERT Exemplar]
Answer:
An Indian ocean is mainly responsible to bring rain bearing monsoon winds to Kerala coast in June every year.

Question 4.
Briefly describe the effect of heat on air pressure.
Answer:
The heat causes air to expand and occupies more space. It becomes lighter. That’s why, warm air is lighter than the cold air.

Question 5.
To expel hot air out of the kitchen, A has an exhaust fan fitted on the window of her kitchen and B has a similar exhaust fan fitted on the wall near the ceiling of her kitchen. Which of the exhaust fan will expel the hot air more effectively? Explain why. [NCERT Exemplar; HOTS]
Answer:
B’s exhaust fan will expel the hot air more effectively because hot air rises up and her fan is at greater height than A’s.

Question 6.
Enlist the other names of cyclone.
Answer:
Hurricane and typhoon are the other names of cyclone.

Question 7.
Suggest some precautions to be taken to prevent the roof of a tin sheet from flying away during a fierce wind storm. [NCERT Exemplar]
Answer:
Some precautions are

Put heavy stones on it.
Screw it tight.

Question 8.
Name the instrument which is used to measure the speed of wind.
Answer:
Anemometer is used to measure the speed of wind.

Question 9.
A flag mounted on a flag post near the sea coast flutters in the direction of sea. At what time of the day does this happen — at mid-night or in the afternoon? [NCERT Exemplar]
Answer:
In the mid-night, the wind blows from land to sea. So, in the mid-night flag mounted on a flag post near the sea coast flutters in the direction of sea.

Question 10.
Figure shows a diagrammatic representation of trees in the afternoon along a sea coast. State on which side is the sea, A or B? Give reasons for your choice. [NCERT Exemplar]

Answer:
In the afternoon, the wind blows from sea to land.
As pressure on the land is less than the pressure above sea, so the sea is on B side.

Question 11.
Name the factor responsible for the increase of speed of wind or cyclones.
Answer:
Factors like wind speed, wind direction, temperature and humidity contribute to the development of cyclones.

Question 12.
Name some cyclones that occurred in the past.
Answer:
Hugo, Katrina, Rita, Hud-Hud and Phailin are the various types of cyclones that occurred in the past.

Question 13.
Can you say why smoke always rises up?
Answer:
As we know that smoke is the combination of hot airs and hot air becomes light weight with respect to cold air. Thus, it always rises up.

Question 14.
In the wind flow pattern, it can be found that the wind shown is not in the exact North-South direction. Explain why.
Answer:
It is because the winds would have blown in the North-South direction either from North to South or from South to North. A change in direction is however caused by the rotation of the earth.

Question 15.
Monsoon winds are helpful. Do you agree?
Answer:
The monsoon winds carry water and it rains. Clouds bring rain and give us happiness. Farmers in our country depend mainly on rains for their harvests. So, monsoon winds are helpful.

Winds, Storms and Cyclones Class 7 Science Extra Questions Short Answer Type Questions

Question 1.
Paheli kept an empty bottle made of plastic inside a refrigerator. After few hours, when she opened the refrigerator, she found the bottle had collapsed. Explain the possible reason. [NCERT Exemplar; HOTS]
Answer:
On cooling the air, contraction of air takes place. The air inside the bottle contracts due to low temperature. Hence, the bottle collapses due to the outside pressure.

Question 2.
Mention an example when the cyclone hit a part of India and how much destruction was caused due to it.
Answer:
Orissa (a part of India) was hit by cyclone in 18th October 1999. The wind speed was 200 km/h and smashed 45000 houses making 700000 people homeless. Another cyclone hit the Orissa again an 29th October with the wind speed of 260 km/h. Thousands of people lost their lives and property worth crores of rupees was destroyed.

Question 3.
When strong/high speed wind blows, an umbrella held upright at times gets upturned. Explain the reason. [NCERT Exemplar]
Answer:
High speed wind passing over the umbrella creates low pressure above the umbrella with respect to below of it. Therefore, the umbrella upturns.

Question 4.
Give three precautions that should be taken to protect oneself from the thunderstorm. [Value Based Question]
Answer:
The following three precautions must be taken to protect oneself from the lightning of thunderstorm

Do not take shelter under an isolated tree.
Do not lie on the ground
Do not take shelter under an umbrella with a metallic end.

Question 5.
Explain thunderstorm and how are they produced.
Answer:
The swift movement of the falling water along with the rising warm air producing sound, lightning, heavy rain and strong wind is called thunderstorm.

Question 6.
Name some effective safety measures against cyclone?
Answer:
On the part of government

Cyclone forecast and warning system must be installed.
Information about cyclone should be given to the people in time through rapid communication system.
Construction of cyclone-shelter in cyclone-prone areas.
Administrative arrangement should be taken to move people faster to safer places.

On the part of the people

People should follow the essential guidelines provided by the agencies through TV radio, phones, etc.
Proper arrangement should be made to shift the essential household goods, domestic animals, etc. to the safer places.
Avoid driving on road which are under water because flood might have damaged the road.
Phone numbers of all the emergency services like police, fire brigade, hospitals, etc. should be kept ready.

These are produced by the dark clouds which form at fairly low altitude in the atmosphere.

Question 7.
Tornado is different from a cyclone. Briefly explain Tornado. What destructions does it cause?
Answer:
These are formed over sea and are called water spouts. Tornado develops from thunderstorm and are formed mostly on the land. These are violent and can reach the speeds of more than 500 km/h destroying everything in their path. These are not very common in India but occurs in Canada and USA.

Most of the tornadoes are weak. When the warm air from the earth’s surface rises up, it whirls around it and causes very high speed winds. These are much smaller than cyclones, i.e. from a few metre to a few hundred metre but the wind speed can rise as high as 500 km/h. The funnel of tornado sucks up everything at its base like dust, debris, cars, trees and even houses.

Question 8.
The advanced technologies issue the alerts and warnings of unexpected storm. Comment.
Answer:
The technologies that include satellites and radars issue the information of expected storm in advance in the form of cyclone warnings. It is issued in two stages, i.e. a cyclone alert or cyclone watch is issued 48 h in advance of any expected storm and cyclone warning is issued 24 h in advance. The message is broadcasted every hour or half hour when a cyclone is nearest the coast.

Question 9.
Monsoon brings rain. Explain the formation of monsoon.
Answer:
During summer, when the land gets warmed and temperature of land becomes higher than that of water in ocean. The air above the land gets heated and rises. Therefore, the cold wind flows from the ocean towards the land. These are monsoon winds which bring water and cause rain.

Question 10.
Due to uneven heating of land and ocean water what happens in the following season?
(a) In winter season
(b) In summer season [HOTS]
Answer:
Due to uneven heating of land and ocean water
(a) In winter season The uneven heating of land and water generates winds from the North-West colder land which carry little water. It brings small amount of rain in winter season.
(b) In summer season The uneven heating of land and ocean water generates wind from the South-West direction. These winds carry lot of water from the Indian ocean.

Question 11.
Rohan was very happy that there was his birthday. He was decorating the room by blowing balloons. He was wondered that most of his balloons burstd. He rushed to his father and asked the reason. His father smiled and explained.
(a) Can you explain the region that why his balloons get burst?
(b) What can be conclude from the condition mentioned?
(c) What are the values shown by Rohan? [Value Based Question]
Answer:
(a) When Rohan blows air into the balloon, the balloon gets inflated due to the pressure exerted by air. But, Rohan observed that most of his balloons burstd. The reason behind it was, he overfilled the air into the balloon. The warm air gets expanded inside the balloon and exerted more and due to the more pressure on the walls of the balloon, balloons burstd.
(b) From the condition mentioned above, it can be concluded that air expands on heating.
(c) Curiosity to learn and scientific attitude.

Question 12.
How are the pressure difference created in nature?
Answer:
Pressure difference is created in the nature by the heat of the sun. When it falls on the earth surface, the surface of the earth gets heated and air above it also gets warm and becomes light weight and moves upward. Thus, the pressure difference is created.

Question 13.
Describe the following terms briefly.
(a) Trade winds
(b) Wester lies
(c) Polar winds
Answer:
(a) The permanent wind that blows towards the equator from North to South are called trade winds.
(b) The wind blowing towards 60° N and 60° S latitudes are called wester lies.
(c) The set of wind blowing from the cold polar regions towards 60° N and 60° S latitudes are called polar winds.

Question 14.
A flat in Mumbai with a balcony facing the sea has some clothes hung on a clothes line in the balcony. Towards which direction, the clothes will be blown in the afternoon? Explain it. [NCERT Exemplar; HOTS]
Answer:
As during the afternoon, the land becomes hot which ultimately creates hot air above it and we know that hot air rises up and there is low pressure created. Thus, winds from sea start blowing towards the land and the clothes will be blown towards the house because sea breeze blowing towards the land.

Question 15.
Briefly explain what are cyclones and how are they formed.
Answer:
High speed winds and air pressure difference can cause cyclones.They are formed when water vapour changes back to liquid by the release of heat. This heat warms air around and it rises to move up and more air rushes to the vacant place. Thus, a cycle is formed which have low pressure and very high speed of air.

Winds, Storms and Cyclones Class 7 Science Extra Questions Long Answer Type Questions

Question 1.
The picture in figure shows tree line along the sea coast on an tops are permanently bent in one direction. Are the trees bendisland near the equator. As shown, the tree towards the sea or away from it? Explain. [NCERT Exemplar]

Answer:
In the given figure, the tree line along the sea coast on an island near the equator shows that tree tops are permanently bent in one direction. The reason behind this movement of tree is that during the day time the wind blows from sea to land because land gets warmer more quickly than sea.

This makes the air of land, warm and lighter which is raised up in the sky. Therefore, the top of the bent trees shows the moving direction of wind from sea to land.

Question 2.
Describe an activity to demonstrate that warm air is lighter than cool air. [NCERT Exemplar]
Answer:
Take two paper bags of same size and hang them in the inverted position at the two ends of metal or wooden stick. Now, tie a piece of strong thread in the middle of the stick. Now, hold the stick by thread. The wooden stick with two paper bags tied to its two ends will hang like a common beam balance. Initially, the wooden stick is perfectly horizontal showing that the two paper bags contain an equal mass of the air.

Caution Perform the experiment with the help of a teacher.

Now, put the burning candle below the open mouth of one side paper bag. We will see that after sometime, the left side of wooden stick goes up showing that it has become lighter than the right side and the balance of the cup is disturbed. The reason for this is that when a burning candle is placed below the one side paper bag, the air above the candle flame gets heated. The hot air being lighter rises up and fills the paper bag above it. Therefore, this side of wooden stick becomes lighter and moves up.
This experiment shows that the air becomes lighter and moves up.

This fact of air is utilised in launching hot air balloons. In nature, there are several situations where warm air rises at a place. The air pressure at that place is lowered. The cold air from the surrounding areas rushes in to fill its place.

Question 3.
State the importance of air pressure. Give reasons for air pressure.
Answer:
The importance of air pressure can be discussed as follows:

It creates wind The difference in atmospheric pressure gives rise to the wind on the earth.
It influences weather Air movement, i.e. downward or upward movement of air, caused due to differences in pressure creates cloudy and clear sky, brings rain or fine weather.
Weather forecasting The changes in air pressure give important clues for weather forecasting. The air pressure is measured by an instrument called barometer.

Question 4.
A cyclone is generated from a thunderstorm. How a thunderstorm becomes a cyclone? Explain.
Answer:
When air moves gently (low speed), it is called a breeze while when it moves violently (high speed), it is called a storm. When the pressure of air drops, it indicates the possibility of a storm.

The swift movement of the falling water along with the rising warm air producing sound, lightning, heavy rain and strong wind is called thunderstorm. It develops in hot and humid tropical areas like India and is accompanied by heavy rains or hail. Thunderstorms are produced by the dark clouds which form at fairly low altitude in the atmosphere. In the tropical area, the air gets warmed up and makes it to rise, whereas humidity provides the water vapour for the formation of cloud.

Therefore, it can be said that to occur a thunderstorm, it requires moisture, rapidly rising warm air and sea breeze or mountains.

Question 5.
Advanced technology has helped people to save them from natural calamities like thunder storm and cyclone. Explain how.
Answer:
During the early part of the last century, the people residing in coastal regions have less than a day for the preparations or to evacuate their homes from an overcoming cyclone. But, the today’s situation is very different. Today we are much protected. We have satellites and radars which can issue the cyclone watch or cyclone alert before 48 hrs (in advance) of any expected storm and a cyclone warning is issued 24 hrs in advance.

Therefore, the coastal residents have sufficient time to prepare and evacuate their homes. The message related to cyclone is broadcasted over the ratio every hour or half hour when a cyclone is nearer the coast.

In this way, the advanced technology has helped us in giving better protection from cyclones. Several national and international organisations cooperate to monitor the cyclone related disasters.

Question 6.
The phenomenon of cloud formation, rain, storm and cyclone are inter linked. Do you agree? If yes, give a flow chart that explain this relation. [HOTS]
Answer:
Yes, the following flow chart explains the phenomenon leading to the formation of cloud, rain, stornrand cyclone.

Rohit0 comments

CHAPTER – 7 Weather, Climate and Adaptations of Animals to Climate | CLASS 7TH | NCERT SCIENCE IMPORTANT QUESTIONS & MCQS | EDUGROWN

SCIENCE IMPORTANT QUESTIONS & MCQS FOR CLASS 7th

Chapter - 7 Weather, Climate and Adaptations of Animals to Climate

Question 1.
Which among the following is generally not predicted in a daily weather report?
(a) Temperature
(b) Pressure
(c) Humidity
(d) Rainfall

Answer

Answer: (b) Pressure

Question 2.
Weather changes
(a) week after week
(b) day after day
(c) within a short period
(d) in any of the above time period

Answer

Answer: (d) in any of the above time period

Question 3.
Rainfall is measured by
(a) rain gauge
(b) water level increase in ponds
(c) water level increase in water table
(d) none of these

Answer

Answer: (a) rain gauge

Question 4.
Given below are some adaptive features of animals:
(i) Layer of fat under the skin
(ii) Long, curved and sharp claws
(iii) Slippery body
(iv) Thick white fur
Which of them are the adaptive features of a polar bear?
(a) (i) only
(b) (i) and (ii) only
(c) (i), (ii) and (iii) only
(d) (i), (ii) and (iv) only

Answer

Answer: (d) (i), (ii) and (iv) only

Question 5.
Which of the following statement is incorrect for penguins?
(a) They huddle together
(b) They cannot swim
(c) They have webbed feet
(d) They have streamlined body

Answer

Answer: (b) They cannot swim

Question 6.
Read the following environmental conditions of tropical rain forests:
(i) Hot and humid climate
(ii) Unequal lengths of day and night
(iii) Abundant rain fall
(iv) Abundant light and moisture
Identify the conditions from the above list that are responsible for the presence of large number of plants and animals in tropical rain forests.
(a) (i) and (ii)
(b) (i) and (iii)
(c) (i), (iii) and (iv)
(d) (ii) and (iv)

Answer

Answer: (c) (i), (iii) and (iv)

Question 7.
The coldest region on earth is the:
(a) polar region
(b) tropical region
(c) temperate region
(d) coastal region

Answer

Answer: (a) polar region

Question 8.
Choose the odd one from the following options:
(a) Thick layer of fat under the skin
(b) White fur
(c) Long grasping tail
(d) Wide and large feet with sharp claws

Answer

Answer: (c) Long grasping tail

Question 9.
Which of the following is not an adaptive feature in polar bear?
(a) White fur
(b) Strong sense of smell
(c) Long curved and sharp claws
(d) Long tail

Answer

Answer: (d) Long tail

Question 10.
Which is the characteristic feature of tropical rainforests?
(a) Hot and humid climate
(b) Enormous number and variety of animals
(c) Competition for food and shelter
(d) All of these

Answer

Answer: (d) All of these

Match the following:

Column A	Column B
(i) Polar bear	(a) Trunk and tusks
(ii) Penguins	(b) Long, large beak
(iii) Birds	(c) Long tail
(iv) Red-eyed frog	(d) Silver-white mane
(v) Toucan	(e) Sticky pads on its feet
(vi) Lion-tailed macaque	(f) Long curved and strong claws
(vii) Elephant	(g) Migrate to warmer region
(viii) New world monkey	(h) Feet have web

Answer

Answer:

Column A	Column B
(i) Polar bear	(f) Long curved and strong claws
(ii) Penguins	(h) Feet have web
(iii) Birds	(g) Migrate to warmer region
(iv) Red-eyed frog	(e) Sticky pads on its feet
(v) Toucan	(b) Long, large beak
(vi) Lion-tailed macaque	(d) Silver-white mane
(vii) Elephant	(a) Trunk and tusks
(viii) New world monkey	(c) Long tail

Fill in the blanks:

1. The maximum temperature of the day occurs generally in the ………………….

Answer

Answer: afternoon

2. In winters the temperature of polar regions can be as low as ………………….

Answer

Answer: 37°C

3. …………………. have white fur. It protects them from predators.

Answer

Answer: Polar bears

4. Like polar bears …………………. are also good swimmers.

Answer

Answer: penguins

5. …………………. must remain warm to survive. They migrate to …………………. regions when winter sets in.

Answer

Answer: Birds,warmer

6. Red-eyed frog lives on ………………….

Answer

Answer: trees

7. …………………. possesses a long, large beak.

Answer

Answer: Toucan

8. Elephant uses its …………………. as a nose.

Answer

Answer: trunk

Choose the true and false statements from the following:

1. Weather can vary over very short periods of time.

Answer

Answer: True

2. In Rajasthan typical desert climate is found.

Answer

Answer: True

3. All the changes in the weather are. driven by the moon.

Answer

Answer: False

4. The polar regions are very cold throughout the year.

Answer

Answer: True

5. A layer of fat under skin is an adaptation against extremely hot climate.

Answer

Answer: False

6. Migration is a mean to escape the harsh, cold conditions.

Answer

Answer: True

7. Tusks of the elephant are the modified teeth.

Answer

Answer: True

8. Lion-tailed macaque feeds mainly on fruits.

Answer

Answer: True

Question 1.
During rainy season, what do we use to protect ourselves from rainwater?
Answer:
We use umbrella or raincoat to protect ourselves from rainwater during rainy season.

Question 2.
A fish dies when taken out of water, whereas a wall lizard will die if kept under water. Mention the term used to describe such abilities that allow fish and lizard to survive in their respective habitats. [NCERT Exemplar; HOTS]
Answer:
Adaptation is the term used to describe such ability. Animals are adapted to survive in the conditions in which they live. So, fish dies when taken out of water while wall lizard dies if kept under water.

Question 3.
Which is the most important factor in determining the climate of a place?
Answer:
The major factor which determines the climate of a place is latitude.

Question 4.
Give one example of an animal that can live both in water and on land. [NCERT Exemplar]
Answer:
Those animals that can live both in water and on land are called amphibian, e.g. frog.

Question 5.
There are several elements of weather. The weather report carries the information about which of the elements of weather?
Answer:
Daily weather reports carry information about the temperature, humidity and rainfall during the past 24 hrs.

Question 6.
Who are meteorologists?
Answer:
The scientist who prepares the weather reports are called meteorologist and the science is called meteorology.

Question 7.
Name the primary sources of energy which cause changes in the weather.
Answer:
The sun is the primary source of energy that causes change in the weather.

Question 8.
When sun rays fall on the earth, what does it provide?
Answer:
Sun provides light as well as heat on the earth.

Question 9.
In North-Eastern regions of India, which type of climate is found?
Answer:
In North-Eastern regions, wet climate is found because it receives rain for major part of the year.

Question 10.
Name two countries that show the tropical rainforests.
Answer:
Tropical rainforest is found in India and central America.

Question 11.
Give the name of few animals that can live in the polar region.
Answer:
Penguin, polar bear, whale, seal and musk oxen live in polar region.

Question 12.
Why is it difficult to predict the weather of a place while it is easy to predict its climate? [NCERT Exemplar; HOTS]
Answer:
Weather is a complex phenomenon which can vary over a short period of time and thus it is difficult to predict the weather of a place while it is easier to predict climate as it is the average weather pattern taken for a long time.

Question 13.
‘Beard ape’ is another name for which animal?
Answer:
Lion-tailed macaque is also known as beard ape.

Question 14.
How is fog formed?
Answer:
During winters when the temperature falls after sunset, it causes condensation of water vapours near the ground.
These droplets hanging in the air form fog.

Question 15.
Mention two adaptive features of penguin that help it in swimming. [NCERT Exemplar]
Answer:
Adaptive features of penguin that help it in swimming are as follows

It has streamlined body.
It has webbed feet.

Question 16.
Some animals have the ability to match their surrounding. Name the property of such animals.
Answer:
This property of animal to blend with its surrounding is called camouflage.

Question 17.
There is a colourful bird that has a long and large beak, and lives in the tropical rainforest. Which bird is this? (HOTS)
Answer:
Toucan is a bird which is colourful with long and large beak, and lives in tropiceal rainforest.

Question 18.
Maximum and minimum temperature is recorded at which time of the day?
Answer:
When the temperature due to the sun’s heat reaches to its maximum level it is called maximum temperature and when it goes down to the lowest level it is called minimum temperature.

Weather, Climate and Adaptations of Animals to Climate Class 7 Science Extra Questions Short Answer Type Questions

Question 1.
The polar bear are white in colour. Explain why.
Answer:
Polar bear have white fur. This is an adaptation of polar bear to blend it with the white background of ice or snow. This helps them to protect from their predators and also to catch their prey.

Question 2.
Name two animals each that live in polar regions and tropical rainforests. [NCERT Exemplar]
Answer:
Polar regions Polar bear/penguin/ reindeer/musk oxen. Tropical rainforests Red-eyed frog /elephants lion-tailed macaque/ lion and tiger.

Question 3.
Write the factors which affect the climate of a particular place.
Answer:
The factors that affect the climate of a place are

Temperature zone or latitude, i.e. amount of sunshine it receives or distance from equator.
Distance from sea.
Altitude or height above the sea level.
Humidity or the presence of moisture in air.
Amount of precipitation received or rainfall.

Question 4.
Some birds migrate from one place to another. What are these birds called? Why do the birds migrate?
Answer:
Migration is the seasonal journey taken by different animals or birds to escape the extreme climatic condition and the search of food, e.g. Siberian cranes migrates towards warmer region in the autumn by travelling several thousands of kilometers.
Some birds are guided by the sun during daytime and by stars during night. Some birds can use the magnetic field of the earth to fnd the direction. Besides birds some fishes, insects and mammals also migrate seasonally in search of more hospitable climates.

Question 5.
Give the difference between weather and climate.
Answer:
Difference between weather and climate

Weather	Climate
It is a day to day condition of atmosphere at a place.	It is the average weather pattern taken over a long period of time (say 25 years).
It varies over a very short period of time (like hour to hour).	It does not vary in a short period of time.
It cannot affect the adaptation of an organism.	Climate affects the adaptions of an organism.

Question 6.
Write two common adaptive features of a polar bear which help in keeping it warm. [NCERT Exemplar]
Answer:
Adaptive features of a polar bear that help in keeping it warm are as follows

They have two thick layers of white fur.
They have layer of fat under their skin.

Question 7.
Differentiate between
(a) weather and climate
(b) humidity and rainfall
(c) climates of polar region and tropical rainforest
(d) maximum and minimum temperatures of the day [NCERT Exemplar]
Answer:
(a)

Weather	Climate
It is a day to day condition of atmosphere at a place.	It is the average weather pattern taken over a long period of time (say 25 years).
It varies over a very short period of time (like hour to hour).	It does not vary in a short period of time.
It cannot affect the adaptation of an organism.	Climate affects the adaptions of an organism.

(b) Humidity indicates the wetness of a place due to the presence of moisture in the atmosphere while rainfall is the drop of water that falls from clouds on the ground.
(c) Polar region remains very cold for most part of the year, whereas tropical rainforest is hot and humid.
(d) Maximum and minimum temperatures of the day indicate highest and lowest recorded temperatures respectively.

Question 8.
There are two animals X and Y. The animal X has yellow brown colour while animal Y has yellow brown colour with black stripes
(a) Name the animals X and Y.
(b) What is the other name for these animals?
(c) Where do these animals live?
(d) Wether these animals are carnivore or herbivore? [HOTS]
Answer:
(a) Animal X with yellow brown colour skin is lion and animals Y with yellow brown colour with black strips on skin is tiger.
(b) These animals are also called as big cats.
(c) These animals live in tropical rainforest.
(d) These animals are carnivores.

Question 9.
The sun plays a major role in the change of weather. How can you explain it?
Answer:
All the changes in a weather are caused due to the sun. The sun is a huge sphere of hot gases at a very high temperature. The sun provides light and heat on the earth.
The energy from the sun is a absorbed and reflected by the earth’s surface, oceans, etc. It plays an important role in determining the weather of any place.
When the water vapour rises high in the atmosphere, it causes rain to come down on the earth. Also the hot air develops high pressure and low pressure areas cause windy weather.

Question 10.
Observe the given figure and answer the following.

(a) Name the birds shown in figure.
(b) What are these birds doing and why?
(c) These birds live in which region? [HOTS]
Answer:
(a) The bird shown in figure is penguin.
(b) Penguins are huddling together to keep them warm.
(c) These birds are found in polar regions.

Question 11.
The animals living in rainforest adapt themselves to the climate present there. How are they adapted to there climatic conditions?
Answer:
The animals that live in tropical rainforests are herbivorous that are able to eat the vegetation, rich in rainforest.
Most of the tropical rainforest animals walk on the land or are adapted to live on trees. The animals living in rainforest have good eyesight and hearing capacity to catch their prey as well as to protect themselves from predators.

Question 12.
Following are the adaptations of some animals
(a) thick skin
(b) diet of fruits
(c) sticky pads on feet
(d) long and large beak
(e) colourful feather
(f) bulging eyes
(g) strong sense of smell
(h) white fur
(i) strong feets
(j) hibernation during winter

Question 13.
Name the animals which shows these adaptations. (HOTS]
Answer:
Tiger
(a) Thick skin
(g) Strong sense of smell
(i) Strong feet.

Toucan
(b) Diet of fruits
(d) Long and large beaks
(e) Colourful feathers

Red-eyed frog
(c) Sticky pads on feet
(f) Bulging eyes

Polar bear
(h) White fur
(j) Hibernation during winter

Weather, Climate and Adaptations of Animals to Climate Class 7 Science Extra Questions Long Answer Type Questions

Question 1.
Rohan went to the desert of Rajasthan with his freinds. He saw an animal. It had a hump. Its feet had large soles. He wondered about this animal. He found that these were adaptations of that animal which helped it to survive in very hot and dry climate of the desert. Answer the following questions on the basis of the observations seen by Rohan.
(a) Name the animal Rohan observed in the desert of Rajasthan?
(b) What role does this hump has in this animal?
(c) Why do it has large soles?
(d) Can you give same more adaptations of this animal which help it to survive in desert?
(e) What values do you observe in Rohan? [Value Bated Question]
Answer:
(a) Rohan observed a camel in the desert of Rajasthan.
(b) The hump stores fat which provides camel with food in times of food shortage.
(c) The feets of camel has large soles which help it to walk on soft sond,
(d) Camel can drink a very large quantity of water at a time which is stored in its stomach. It sweats very little which helps it to conserve water. Also it excretes very little water in the form of urine.
(e) Rohan is observant, curious and adventurer. He asks intelligent questions.

Question 2.
Write in detail about the adaptations in different animals living in tropical rainforests.
Answer:
The tropical region lies near both the sides of equator line on the earth. These regions are hot but get plenty of rainfall. Therefore, this region is humid. Even in coldest month, the temperature is generally higher than about 15°C. During hot summers, the temperature may cross 40°C. Days and nights are almosts equal in length throughout the year. Tropical rainforest is the important feature of tropical region. These regions are rich in vegetation and large diversity in animals is also seen in this region.

Adaptations in Red-eyed Frog: The red-eyed frog lives on trees in tropical rainforest. They have sticky pads on their feet that help them to climb trees. It does not live in water and has a green back and a creamy underside. It has big and bulging bright-red eyes and it is a nocturnal. It sleeps during the day and becomes active during night and feeds on the insects present on the tree. The bulging eye of frog protects it from its predator. The sudden opening of big and bright-red eyes frightens the predator for a while and in the meantime the frog gets time to jump to a safe place. The green colour of the frog helps it to hide within the green leaves of the tree and helps it to protect from predators.

Adaptations in Monkey: The monkeys living in tropical rainforests have long tails for grasping branches. Their hands and feet are adapted in such a way that they can easily hold the branches of trees. The eyesight of monkeys is very good which helps them in leaping between the branches to escape from their predators. Monkeys eat fruits, seeds, leaves, root and insects as their food which is present in abundance in tropical rainforest.

Adaptations in Lion-Tailed Macaque: It is also called as beard ape and lives in the rainforest of Western Chats in India. It has silver-white mane which surrounds the head from the cheeks down to its chin which is the specific characteristic of this animal. It is called lion-tailed because its tail is like that of lion having bunch or tuft of hair at the end.

They spend most of their time feeding in the upper canopy of trees (i.e. arboreal animal). It mainly feeds on fruits, seeds, young leaves, stems, flowers and buds. They also can eat insects present under the bark of the tree. Since, it is able to get sufficient food on trees. It rarely comes down on the ground and spends a major part of its life on the tree. It is a good climber with its hand and feet adapted to hold the branches of trees firmly.

Adaptation in Toucan: Toucan is a bird, which is found in tropical rainforest and which possesses a long strong and large beak. This bird is adapted for tropical rainforest in several ways. It is colourful bird which possesses a strange beak. It lives most of the time in the holes of big trees.

The long and large beak helps Toucan to reach the fruits attached to the ends of even thin branches of tree that are weak enough to support its weight. It is an adaptation of this bird to get the unreachable fruits. Its large beak also helps in temporary storage of fruits which is collected by Toucan. These possess feet that are adapted for grasping the branches of trees firmly. Toucan can change the colour of its feather, so as to get mixed up with the surrounding and they are not easily noticed by predators and remain safe.

Adaptations in Lion and Tiger: These are also called as big cats and are carnivore which eat only flesh of other animals. These have following adaptations to survive in tropical rainforest:

They have thick skin and skin colour helps them to camouflage (ability of the animal to match their surrounding, e.g. chameleon, butterfly). The yellow brown colour of lion and black stripes of tiger helps them to hide in the forest by blending with the surroundings. It helps these carnivores to catch their prey.
They have strong sense of smell which helps them to locate their prey.
They also develop sensitive hearing capacity to find its prey.
They have eyes in front of their head which enable them to have a correct idea of the location of their prey. They also have good eyesight.
Their strong legs help them to run fast and long, sharp and strong claws in front of their legs help them to catch and tear their prey.

Adaptations in Elephant: Elephant is a well-known animal of Indian tropical rainforest. These are plant eaters and are adapted in many remarkable ways to survive in tropical rainforest. These adaptations can be discussed as follows:

The elephant has a long trunk which is used as nose and has a strong sense of smell. It also helps elephant to pick up the food. The long trunk is also used for breathing. It can reach up to the branches of trees and help it to eat tree leaves. It is used for sucking water from lakes or rivers (drinking).
The elephant possesses tusks (long pointed teeth) that are used in tearing the bark of trees which the elephant loves to eat as food. It also helps elephant to fight their enemies and protecting themselves.
The elephant has large ears that help it to hear even very soft sounds and can sense the danger. It also helps the elephant to keep it cool in the hot and humid climate of the tropical forest.
The feet of elephant are large and round which help it to provide good stability and also prevent it from sinking into soft ground due to its heavy weight.

Question 3.
In a class, the teacher was explaining a concept from weather and climate chapter. Anand got confused and slowly asked his teacher to repeat again. She smiled and started again. In equatorial belt the climate is hot and wet. It has evergreen rainforest and variety of plants. Similarly the vegetation of tropical region also has variations. The forest located between two tropics is called tropical forest. Desert shows arid region and only xerophytes are observed. These plants show specific modification for their survival in this arid region.
(a) Which type of forest is formed in equatorial region?
(b) What are the variation in vegetation seen in tropical forest?
(c) Give some adaptations of plants that are formed in desert.
(d) Some places conifers are seen. What are these places?
(e) What values do we observe in the teacher and Ar\and? [Value Baaed Question]
Answer:
(a) Evergreen rainforest with the greatest variety of plants are seen in equational region.
(b) In tropical regions, vegetation varies from broad leaves evergreen trees to tropical deciduous trees to grassland.
(c) The plants in the arid of desert regions have modified leaves covered with hair or waxy coating and an extensive root system.
(d) Conifers are maintained and adapted to withstand snow fall and shortage of water in colder belt.
(e) Anand is observant and sincere boy. He is not afraid to ask question in the class.

Question 4.
The following graph shows the change in temperature. Answer according to the reading of graph.
(a) Draw a table and fill the temperature change of each day.
(b) Which day show the highest temperature?
(c) Which day shows the minimum temperature?

Answer:
(a) Table showing the reading of temperature from the graph:

Date	Maximum temperature
03/11/14	26.0°C
04/11/14	23.5°C
05/11/14	25.0°C
06/11/14	22.0°C
07/11/14	25.5°C
08/11/14	23.3°C
09/11/14	24.4°C

(b) The highest temperature is seen on 3rd November, 2014.
(c) The lowest temperature or minimum temperature was seen on 06th November, 2014.

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CHAPTER – 7 Weather, Climate and Adaptations of Animals to Climate | CLASS 7TH | NCERT SCIENCE IMPORTANT QUESTIONS & MCQS | EDUGROWN

SCIENCE IMPORTANT QUESTIONS & MCQS FOR CLASS 7th

Chapter - 7 Weather, Climate and Adaptations of Animals to Climate

Question 1.
Which among the following is generally not predicted in a daily weather report?
(a) Temperature
(b) Pressure
(c) Humidity
(d) Rainfall

Answer

Answer: (b) Pressure

Question 2.
Weather changes
(a) week after week
(b) day after day
(c) within a short period
(d) in any of the above time period

Answer

Answer: (d) in any of the above time period

Question 3.
Rainfall is measured by
(a) rain gauge
(b) water level increase in ponds
(c) water level increase in water table
(d) none of these

Answer

Answer: (a) rain gauge

Answer

Answer: (d) (i), (ii) and (iv) only

Question 5.
Which of the following statement is incorrect for penguins?
(a) They huddle together
(b) They cannot swim
(c) They have webbed feet
(d) They have streamlined body

Answer

Answer: (b) They cannot swim

Answer

Answer: (c) (i), (iii) and (iv)

Question 7.
The coldest region on earth is the:
(a) polar region
(b) tropical region
(c) temperate region
(d) coastal region

Answer

Answer: (a) polar region

Question 8.
Choose the odd one from the following options:
(a) Thick layer of fat under the skin
(b) White fur
(c) Long grasping tail
(d) Wide and large feet with sharp claws

Answer

Answer: (c) Long grasping tail

Question 9.
Which of the following is not an adaptive feature in polar bear?
(a) White fur
(b) Strong sense of smell
(c) Long curved and sharp claws
(d) Long tail

Answer

Answer: (d) Long tail

Question 10.
Which is the characteristic feature of tropical rainforests?
(a) Hot and humid climate
(b) Enormous number and variety of animals
(c) Competition for food and shelter
(d) All of these

Answer

Answer: (d) All of these

Match the following:

Column A	Column B
(i) Polar bear	(a) Trunk and tusks
(ii) Penguins	(b) Long, large beak
(iii) Birds	(c) Long tail
(iv) Red-eyed frog	(d) Silver-white mane
(v) Toucan	(e) Sticky pads on its feet
(vi) Lion-tailed macaque	(f) Long curved and strong claws
(vii) Elephant	(g) Migrate to warmer region
(viii) New world monkey	(h) Feet have web

Answer

Answer:

Column A	Column B
(i) Polar bear	(f) Long curved and strong claws
(ii) Penguins	(h) Feet have web
(iii) Birds	(g) Migrate to warmer region
(iv) Red-eyed frog	(e) Sticky pads on its feet
(v) Toucan	(b) Long, large beak
(vi) Lion-tailed macaque	(d) Silver-white mane
(vii) Elephant	(a) Trunk and tusks
(viii) New world monkey	(c) Long tail

Fill in the blanks:

1. The maximum temperature of the day occurs generally in the ………………….

Answer

Answer: afternoon

2. In winters the temperature of polar regions can be as low as ………………….

Answer

Answer: 37°C

3. …………………. have white fur. It protects them from predators.

Answer

Answer: Polar bears

4. Like polar bears …………………. are also good swimmers.

Answer

Answer: penguins

5. …………………. must remain warm to survive. They migrate to …………………. regions when winter sets in.

Answer

Answer: Birds,warmer

6. Red-eyed frog lives on ………………….

Answer

Answer: trees

7. …………………. possesses a long, large beak.

Answer

Answer: Toucan

8. Elephant uses its …………………. as a nose.

Answer

Answer: trunk

Choose the true and false statements from the following:

1. Weather can vary over very short periods of time.

Answer

Answer: True

2. In Rajasthan typical desert climate is found.

Answer

Answer: True

3. All the changes in the weather are. driven by the moon.

Answer

Answer: False

4. The polar regions are very cold throughout the year.

Answer

Answer: True

5. A layer of fat under skin is an adaptation against extremely hot climate.

Answer

Answer: False

6. Migration is a mean to escape the harsh, cold conditions.

Answer

Answer: True

7. Tusks of the elephant are the modified teeth.

Answer

Answer: True

8. Lion-tailed macaque feeds mainly on fruits.

Answer

Answer: True

Important Questions