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CLASS 6TH | UNIT 6: DATA HANDLING | Data Handling (Including pictograph and bar graph)| REVISION NOTES

Data: A collection of numbers gathered to give some information.


Recording Data: Data can be collected from different sources.


Pictograph: The representation of data through pictures of objects. It helps answer
the questions on the data at a glance.


Bar Graph: Pictorial representation of numerical data in the form of bars (rectangles)
of equal width and varying heights.

  • We have seen that data is a collection of numbers gathered to give some information.
  • To get a particular information from the given data quickly, the data can be arranged
    in a tabular form using tally marks.
  • We learnt how a pictograph represents data in the form of pictures, objects or parts of
    objects. We have also seen how to interpret a pictograph and answer the related
    questions.
  • We have drawn pictographs using symbols to represent a certain number of items or
  • things.
  • We have discussed how to represent data by using a bar diagram or a bar graph. In a
  • bar graph, bars of uniform width are drawn horizontally or vertically with equal
  • spacing between them. The length of each bar gives the required information.
  • To do this we also discussed the process of choosing a scale for the graph.

For example, 1 unit = 100 students. We have also practiced reading a given bar graph. We
have seen how interpretations from the same can be made.

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Class 6th | Unit 1: Numbers | Playing With Numbers | Revision Notes

We have discussed multiples, divisors, factors and have seen how to identify factors and
multiples.


We have discussed and discovered the following:


(a) A factor of a number is an exact divisor of that number.


(b) Every number is a factor of itself. 1 is a factor of every number.


(c) Every factor of a number is less than or equal to the given number.


(d) Every number is a multiple of each of its factors.


(e) Every multiple of a given number is greater than or equal to that number.


(f) Every number is a multiple of itself.


We have learnt that –


(a) The number other than 1, with only factors namely 1 and the number itself, is a
prime number. Numbers that have more than two factors are called composite
numbers. Number 1 is neither prime nor composite.


(b) The number 2 is the smallest prime number and is even. Every prime number
other than 2 is odd.


(c) Two numbers with only 1 as a common factor are called co-prime numbers.


(d) If a number is divisible by another number then it is divisible by each of the
factors of that number.


(e) A number divisible by two co-prime numbers is divisible by their product also.
We have discussed how we can find just by looking at a number, whether it is
divisible by small numbers 2,3,4,5,8,9 and 11. We have explored the relationship
between digits of the numbers and their divisibility by different numbers.


(a) Divisibility by 2,5 and 10 can be seen by just the last digit.


(b) Divisibility by 3 and 9 is checked by finding the sum of all digits.


(c) Divisibility by 4 and 8 is checked by the last 2 and 3 digits respectively.


(d) Divisibility of 11 is checked by comparing the sum of digits at odd and even places.
We have discovered that if two numbers are divisible by a number then their sum
and difference are also divisible by that number.


We have learnt that –


(a) The Highest Common Factor (HCF) of two or more given numbers is the highest of
their common factors.


(b) The Lowest Common Multiple (LCM) of two or more given numbers is the lowest
of their common multiples.

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Class 6th | Unit 1: Numbers | Estimation | Revision Notes

Estimation And Approximation

When someone gets you a surprise gift you are likely to estimate its approximate cost. Thus, in English estimation is the rough calculation of the value or the extent of something. Similarly, an approximation is a value that is nearly correct but not exact.

In mathematics, you will come across many situations where in you need to estimate.

Estimation means to make a judgment of quantities, approximate calculation of size,  cost, population etc.

Approximation means almost correct amount. The word approximation is derived from Latin approximatus, from proximus meaning very near and the prefix, ap- meaning to.

In this chapter, you will learn about estimation and approximation.

The procedure of estimation depends upon the following:

  • The degree of accuracy required.
  • The simplicity of computation.
  • How quickly is the estimation completed?
  • How quickly would the guessed answer be obtained?

Let us consider some of the examples:

Example 1:

Estimate the sum (69 + 73) as nearest ten.

Solution:

          Round off each given number to nearest ten.

69 = 70

73 = 70

Required sum = 70+ 70 = 140

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CLASS 6TH | UNIT 2:  RATIO, PROPORTION AND ARITHMETIC PROBLEMS | DECIMAL | REVISION NOTES

Introduction to Decimals

Fractional numbers whose denominators ar 10 , 100, 1000 etc, are called decimal fractions or
decimals.
The dot “ . “ is called the decimal point.
For Example : (i) 3
10
is expressed as 0.3
(ii) 1
100
is expressed as 0.01
II. Conversion of Decimals
Example : convert the following fraction into decimals
(i)


Solutions : 8÷3 = 0.375



= 5.375


III . Conversion of Units :
1 kilometre = 1000 metres
1 metre = 100 centimetres
1 centimetre = 10 milimetres
1 decimetre = 10 centimetre
1 metre = 10 decimetres
1 hectomere = 10 decametres
1 Kilometre = 10 hectometres

III . Conversion of Mass :
1 kilometre = 1000 grams
1 grams = 100 centigrams
1 centigram = 10 miligrams
1 decigram = 10 centigrams
1 gram = 10 decigram
1 hectogram = 10decagrams
1 Kilogram = 10hectograms

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Class 6th | Unit 2:  Ratio, Proportion And Arithmetic Problems | Fractions | Revision Notes

Introduction to Fraction


A fraction means a part of a whole (group or region). Every fraction has a numerator and a
denominator.
In the fraction 3/5 , 3 is the numerator part and 5 is the denominator part.


Types of Fraction:-
(i) Proper Fraction: Fraction in which the numerator is less than the denominator, is called
proper fraction. For eg: 4/5 , 6/11, 999/1000.
(ii) Improper Fraction: Fraction in which the numerator is either equal to or greater than
the denominator, is called the improper fraction. For eg: 3/5 , 6/5, 1000/999.
(iii) Like Fraction: Fraction having the same denominator are called like fractions. For eg:
3/5, 5/5, 6/5
(iv) Unlike Faction: Fraction having different denominators are called unlike fractions. For
eg: 3/5, 4/3, 4/7
(v) Mixed Fraction : Mixed Fraction like 1 4
1
(vi) Equivalent Fraction:Two or more factions having the same value or representing the same part of whole are called
equivalent fraction.
Example. Write an equivalent fraction of 4/5 with numerator as 12.
Solution:- 1
st Method : To get 12 as the numerator, we have to multiply 4 by 3. Therefore,
denominator 5 should also be multiplied by 3.

So, 4/5 = 4 x 3
5 x 3
= 12/15
2
nd Method : 4 12
5 ?
= 4 x ? = 12 x 5
12 x 5
4
= 15
So, 4/5 = 12/15
Hence, 12 / 15 is an equivalent fraction of 4/5
Example :
Meera cuts 54 m of cloth into some pieces, each of length 3 3/8 meters. How many pieces does she
get.
Solution :
Total length of clothe = 54m
Length of each piece = 3 3/8
m = 27/8 m
No. of pieces formed = 54 / 27/8
= 54 x 8 /27
= 16
Hence , 16 pieces each of length 3 3/8 m can be cut down from the cloth of 54 m length.

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Class 6th | Unit 1: Numbers | Sets | Revision Notes

Conceptual division:-
• Introduction of Set :
A set is a collection or group of objects/elements which have a similar characters.


• Way of Representing Set
a. Elements of a Set
b. Properties of Set


• Representation of Set
a. Listing Method (Roster form)
b. Rule Method ( Set-builder form)


• Types of Set
a. Equal Sets
b. Empty Set or Null Set or Void Set
c. Non-Empty Set or Overlapping Set
d. Singleton Set
e. Finite Set
f. Infinite Set
g. Null or Empty or Void Set
h. Equivalent Set
i. Disjoint Set
j. Cardinality of Set


• Examples :
• Disjoint Set


Q.1 Two sets are given by A = x , y, z and B = 1,2,3,4,5


Solution : Clearly , sets A and B have no element common to both . Therefore sets A and B
are disjoint sets.


Q.2 Find the cardinality of the set
A = 2 , 4,8,10,12


Solution : Since , set A = 2, 4, 8, 10, 12 has total 5 elements. Hence , the cardinality of the set A
is 5.

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Unit 3 Utility Service of Banking Notes| Class 9th Banking & Insurance Revision Notes

Unit 3 Utility Service of Banking Notes| Class 9th Banking & Insurance Video

Detailed Explanation of Unit 3: Utility Services of Banking

1. Credit Cards & Debit Cards

Modern banking provides two essential payment instruments: credit cards and debit cards, each catering to different financial needs.

A. Credit Cards

A credit card allows the user to borrow funds up to a pre-approved limit to pay for goods and services.

  • Features:
    1. Buy now, pay later: Allows deferred payment.
    2. Interest-free period: Typically 30–50 days if the bill is cleared on time.
    3. Reward programs: Cashback, discounts, or reward points on purchases.
Real-Life Example:

An individual uses a credit card to book flight tickets online, earning reward points redeemable for discounts on future purchases.

B. Debit Cards

A debit card deducts money directly from the user’s bank account for transactions.

  • Features:
    1. Direct payment from savings/current account.
    2. No interest or borrowing involved.
    3. Suitable for people managing expenses within their account balance.
Real-Life Example:

A customer pays for groceries using their debit card, with the amount deducted immediately from their savings account.

C. Differences Between Credit and Debit Cards
FeatureCredit CardDebit Card
Payment ModeBorrowed fundsOwn account balance
InterestCharged on overdue paymentsNo interest
EligibilityRequires a good credit scoreAvailable to most account holders
Use in EmergenciesSuitable for large purchasesLimited by account balance
Solution Example:

Q1. Differentiate between credit and debit cards with examples.
Ans:

  • A credit card allows borrowing funds, while a debit card deducts money from the user’s account.
  • Example: Booking tickets with a credit card involves borrowed money, while paying bills with a debit card uses personal funds.

2. Automated Teller Machines (ATMs)

ATMs are self-service banking terminals enabling customers to perform various financial transactions.

A. Functions & Uses of ATMs
  1. Cash withdrawal: Convenient access to funds anytime.
  2. Balance inquiry: View account balances instantly.
  3. Fund transfer: Transfer money between accounts.
  4. Bill payments: Pay utility bills directly via ATMs.
Real-Life Example:

A traveler withdraws cash from an ATM during a holiday in a remote town.

B. Customer Complaints Management for ATM Transactions
  1. Common Issues:
    • Cash not dispensed but debited.
    • Card stuck or malfunctioning.
  2. Resolution Process:
    • Register complaints via helpline, online portals, or branch visits.
    • Resolution typically occurs within 7 working days.
C. Evolution of ATMs
  1. First ATM: Introduced in the late 1960s.
  2. Technological Advancements: From simple cash dispensing to complex transactions like deposits and fund transfers.
D. Structure of ATMs
  1. Input Devices: Keypad and card reader.
  2. Output Devices: Display screen, receipt printer, and cash dispenser.
  3. Software: Ensures secure and seamless transactions.
Solution Example:

Q2. What are the functions of ATMs, and how do they resolve customer complaints?
Ans:
Functions: Cash withdrawal, balance inquiry, fund transfer, and bill payments.
Complaint Resolution: Customers can report issues through helplines or branches, with most problems resolved within 7 days.

3. Core Banking

Core banking refers to centralized systems enabling customers to access their accounts and services from any branch or digital platform.

Features of Core Banking:
  1. Anywhere Banking: Access accounts from any branch or ATM.
  2. Real-Time Processing: Instant transaction updates.
  3. Digital Services: Internet and mobile banking integration.
Real-Life Example:

A customer deposits a cheque at a branch in Mumbai, and the amount is accessible in their Delhi branch account instantly.

Solution Example:

Q3. What are the features of core banking?
Ans:
Core banking allows real-time processing, anywhere banking, and digital services integration, ensuring customer convenience.

4. Standing Instructions

Standing instructions are predefined orders given by customers to banks to execute recurring payments like utility bills or loan EMIs.

a. Specimen of Standing Order:

Date: [DD/MM/YYYY]
To: [Bank Name]
Subject: Standing Instruction for Monthly Payment
Instruction: Debit ₹5,000 monthly from my account for electricity bill payment.

Solution Example:

Q4. Define standing instructions with an example.
Ans:
Standing instructions automate recurring payments. Example: Setting up an order to pay monthly rent via account debit.

Summary

Utility services such as credit/debit cards, ATMs, core banking, and standing instructions have transformed banking, enhancing convenience and efficiency for customers. These tools cater to diverse financial needs and simplify banking experiences.

10 Most Important Questions with Detailed Solutions

  1. Differentiate between credit and debit cards.
    Ans: Credit cards use borrowed funds, while debit cards deduct from the user’s account balance.
  2. List the uses of ATMs.
    Ans: Cash withdrawal, balance inquiry, fund transfer, and bill payments.
  3. Explain the role of core banking in modern banking services.
    Ans: Core banking enables anywhere banking, real-time processing, and digital service integration.
  4. What are standing instructions? Provide an example.
    Ans: Standing instructions automate recurring payments. Example: Loan EMI payments.
  5. State the features of credit cards.
    Ans: Deferred payment, interest-free periods, and reward programs.
  6. What is the process for resolving ATM complaints?
    Ans: Complaints can be filed via helplines, online portals, or bank branches, resolved within 7 days.
  7. What is the evolution of ATMs?
    Ans: Initially introduced for cash dispensing, ATMs now support deposits, fund transfers, and more.
  8. What are the advantages of core banking for customers?
    Ans: Ensures flexibility, instant transaction updates, and digital convenience.
  9. Describe the structure of ATMs.
    Ans: Includes input devices (keypad, card reader), output devices (screen, printer, dispenser), and secure software.
  10. Explain how ATMs support real-life scenarios.
    Ans: ATMs provide 24/7 access to cash and services, ensuring convenience during emergencies.

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ICSE Class 6 Maths Chapter 1 Number System revision notes

Concept 1: Hindu – Arabic System of Numeration


In this system, we use ten symbols namely: 0, 1, 2,3,4,5,6,7,8 and 9 to represent any number. These symbols are called digits.

Concept 2: Place value and Face value

  1. Place value of a digit in a number depends on the place it occupies in the number
  2. The face value of a digit is the digit itself
  3. ‘0’ is the only digit whose face value and place value both are same, i.e. the face value of 0 is 0 and place value of 0is also 0.

Example 1. Find the place value of all the digits in the number 35268
Soln. In the number 35268, we have
• The place value of 8 = 8 x 1 = 8
• The place value of 6 = 6 x 10 = 60
• The place value of 2 = 2 x 100 = 200
• The place value of 5 = 5 x 1000 = 5000
• The place value of 3 = 3 x 10000 = 30000


Expanded form of a number: A number is expanded on the basis if the place values of the digits. For instance,
Number = unit’s place x (unit) + ten’s place x (10) + hundredth place x (100) + thousand’s place x (1000) + … and so on.
Comparison of 2 numbers: To decide which one is bigger, remember the following:
1) Of the 2 numbers the number having more digits is bigger
2) If 2 numbers have an equal number of digits, then the number having the larger digit in the leftmost place is bigger. If the digit in the leftmost place are equal then the number having the larger digit in the place on the right of the equal digits is bigger, and so on

Example 2. Compare the numbers:

  1. 8325 and 14103
  2. 60714 and 52130
    Soln.
    1) The first number has four digits while the second has five digits. So, the second number is bigger.
    2) The 2 numbers have an equal number of digits, however, 6<5. So, 60714 is the biggest number.

Concept 3: Natural number and Whole number

Natural number and Whole number


Natural number: The counting number 1, 2,3,4,5,6, …, are called natural numbers.
1 is the first and the smallest natural number. Any natural number can be obtained by adding 1 to its previous natural number.
There is no last or largest natural number. Therefore, there are infinite whole numbers.


Whole number: The number ‘0’ altogether with natural number, called whole numbers, i.e. 0,1,2,3,4,5, … etc. are called whole numbers
0 is the first and the smallest whole number
There is no last or largest whole number. Therefore, there are infinite whole numbers.
Examples:

  1. Find the face values of all the digits in the number 83245.
    Soln. In the number 83245
    • The face value of 5 is 5.
    • The face value of 4 is 4.
    • The face value of 2 is 2.
    • The face value of 3 is 3.
    • The face value of 8 is 8.

  1. Find all the possible three digit numbers using the digits 1,3,5 taking each diggings
    Keeping 1 at the ones place the numbers formed are 751 and 571
    Keeping 5 at the ones place, the numbers formed are 157 and 517
    So, the required numbers are 751, 571, 175, 715, and 157,517.
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CHAPTER -5 Water | CLASS 7TH | NCERT GEOGRAPHY IMPORTANT QUESTIONS & MCQS | EDUGROWN

Chapter -5 Water

MCQs

Question 1.
Which is the process through which water continuously changes its form?
(a) Water cycle
(b) Food cycle
(c) Rain
(d) All of these

Answer

Answer: (a) Water cycle

Question 2.
Which water is salty?
(a) River water
(b) Pond water
(c) Rain water
(d) Sea water

Answer

Answer: (d) Sea water

Question 3.
Which one of the following is an artificial enclosure for keeping small house plants?
(a) Terrarium
(b) Thermosphere
(c) Climate
(d) Evaporation

Answer

Answer: (a) Terrarium

Question 4.
Sea water contains
(a) 97.3% of salt
(b) 2% of salt
(c) 0.68% of salt
(d) 0.973% of salt

Answer

Answer: (a) 97.3% of salt

Question 5.
Which day of the year is celebrated as Water Day?
(a) 26 January
(b) 15 January
(c) 15 August
(d) 22 Marc

Answer

Answer: (d) 22 March

Question 6.
The movements that occur in oceans can be broadly called
(a) wave
(b) circulation
(c) water cycle
(d) all of these

Answer

Answer: (b) circulation

Question 7.
Which is the Japanese word which means ‘Harbour Waves’?
(a) Tsunami
(b) Sea wave
(c) Ocean wave
(d) None of these

Answer

Answer: (a) Tsunami

Question 8.
When did Tsunami strike the Indian ocean?
(a) 26 December, 2004
(6) 26 December, 2005
(c) 26 December, 2006
(d) 26 December, 2007

Answer

Answer: (a) 26 December, 2004

Question 9.
The largest Tsunami wave travels at the speed of
(a) more than 700 km per hour
(b) more than 500 km per hour
(c) more than 250 km per hour
(d) more than 100 km per hour

Answer

Answer: (a) more than 700 km per hour

Question 10.
The rhythmic rise and fall of ocean water twice in a day is known as
(a) tide
(b) wave
(c) ocean current
(d) none of these

Answer

Answer: (a) tide

Question 11.
The Labrador and Gulf stream are the examples of:
(a) Tides
(b) Ocean currents
(c) Tsunami
(d) Waves

Answer

Answer: (b) Ocean currents

Match the contents of Column A with that of Column B

Column AColumn B
1. Spring tides(а) Between Europe and Africa
2. Gulf stream(b) Cold current
3. Labrador current(c) Low tide
4. Neap tides(d) High tide
5. Mediterranean sea(e) Warm current
Answer

Answer:

Column AColumn B
1. Spring tides(d) High tide
2. Gulf stream(e) Warm current
3. Labrador current(b) Cold current
4. Neap tides(c) Low tide
5. Mediterranean sea(а) Between Europe and Africa

Fill in the blanks with appropriate words:

1. The major sources of fresh water are rivers and ……………

Answer

Answer: springs and glaciers (Any one)

2. About ………….. % of water is present in the oceans and …………….. % as ice-caps.

Answer

Answer: 97.3, 02.0

3. The movements that occur in oceans are waves, …………. and ………….

Answer

Answer: tides, currents

4. …………. Point in the Andaman and Nicobar islands got submerged after the tsunami of 2004.

Answer

Answer: Indira

5. High tides help in ………….. and fishing.

Answer

Answer: navigation

6. …………. sea is the largest lake.

Answer

Answer: Caspian.

State whether the given statements are true or false.

1. We have about 0.68% of water as ground water.

Answer

Answer: True

2. Ocean water is calm and still.

Answer

Answer: False

3. Tsunami can be caused by underwater landslides.

Answer

Answer: True

4. Tides are highest on a full or new moon day.

Answer

Answer: True

5. Cold currents carry water from lower latitudes to poles.

Answer

Answer: False

6. Tides help in generating electricity.

Answer

Answer: True

Question 1.
When you think of water, what images came to your mind?
Answer:
Three states of water: solid, liquid and gaseous.

  • Water running in rivers, canals, streams etc.
  • Frozen and moving like glaciers.
  • In the form of steam (evaporation)
  • In the form of droplets (condensation)
  • Falling as rainfall (Rainfall)
  • As ground water/Water in taps.
  • In the wells, ponds, pools etc

Question 2.
Where do the puddles of water vanish?
Answer:
Most of the water percolates into the ground.

  • The sun’s heat evaporates the water as vapours. On cooling these vapours condenses and forms clouds
  • Then this water may fall on land or sea as rain, snow or sleet.

Question 3.
What is water cycle?
Answer:
The continuous circulation of water between oceans, atmosphere and land is called water cycle.

Question 4.
What is a terrarium?
Answer:

  • A terrarium is an artificial enclosure used for keeping small house plants.
  • Our earth is like a terrarium.

Question 5.
Why is our earth like a terrarium?
Answer:
Our earth is like a terrarium as the water which existed centuries ago still exists. The water used to irrigate fields in Haryana might have in Amazon River centuries ago.

Question 6.
Name the sources of fresh water.
Answer:

  • Rainfall, snow, rivers, ponds, springs and glaciers etc.
  • Water from underground.

Question 7.
Why is sea water salty?
Answer:
There is a large amount of water in seas and oceans but it is salty or saline. It is because it contains a large amount of dissolved salts like sodium chloride or common salt.

Distribution of Water Bodies

Question 1.
Define salinity.
Answer:
Salinity is the amount of salt in grams present in 1000 grams of water. The average salinity of oceans is 35 parts per thousand (= 0.035%)

Question 2.
Discuss the distribution of water bodies.
Answer:

  • Nearly 75% of the earth’s surface is covered with water.
  • There is more water than land on the earth, still so many countries face water scarcity due to the fact that most of this water is salty or it is polluted beyond use.
  • Moreover all the water on the earth is not available to us.
  • The following table gives the distribution of water in percentage.

Water Class 7 Extra Questions Geography Chapter 5 - 2

Question 3.
Why is water important to us? Suggest few ways to conserve water.
Answer:
Water is very necessary for us. Water alone can quench the thirst thirsty.
Water is needed for survival of plant and animal life.
Water is very essential and we should conserve it:

  • By not wasting it during brushing, bathing, washing etc.
  • By trapping the rain water by water shed development or rain water harvesting.
  • By recycling water.
  • By making check dams and bunds on the fields etc.

Question 4.
Swimmers can float in dead sea. Give reasons.
Answer:
Dead Sea in Israel has salinity of 45 parts per thousand and there the water is dense making it easier for swimmers to float.

Ocean Circulation

Question 1.
What is so magical or fascinating about sea?
Answer:
The continuous movement of ocean water is fascinating. The wet sand on beach, sea birds, the salty cool breeze, rhythmic movement of waves attracts one and all. On the other hand the water of ponds, lakes etc is calm.

Question 2.
Which movements occur in oceans?
Answer:The movements of oceans are categorized as tides, currents and waves.

Waves

Question 1.
What are sea waves?
Ans,
Sea Waves:

  • When the water on the surface of the ocean rises and falls alternately, they are called waves.
  • When we are playing throw ball on the beach and the ball falls into the water, it begins to go up and down.
  • It is fun that the ball gets washed back to the shore by the waves.

Question 2.
How are Tsunamis formed? How do they cause destruction?
Answer:
Tsunami is a Japanese word meaning harbour waves.

  • Winds blowing at high speed during a storm form huge waves.
  • An earthquake, volcanic eruption or underwater landslides can shift large amount of ocean water.
  • These tidal waves called Tsunami may be as high as 15 m. It travels at a speed of more than 700 km/hr.
  • The areas near the coasts get submerged and it leads to earthquakes also.

Question 1.
Briefly write about the sequence of events leading to Tsunami of 2004 in the Indian Ocean.
Answer:
Tsunami of 26 December 2004 was the result of the earthquake that had its epicentre close to western boundary of Sumatra. It caused havoc in the Indian Ocean.

  • Due to the earthquake measuring 9.0 on Richter scale the Indian plate went under Burma plate.
  • The ocean floor was displaced by about 10-20 m. Huge mass of ocean water flowed to fill the gap.
  • After thrusting the Indian plate and Burma plate, this water rushed back towards the coastline.
  • Tsunami at the speed of 800km /hr washed some of the islands in the Indian Ocean.
  • As the wave moved away from the epicentre of earthquake the speed declined 700-900km/hr to 70-80km/hr.
  • Waves travelled up to a depth of 3 km from the coast:

Question 4.
What were the effects of the Tsunami?
Ans.
Tsunami caused severe destruction.

  • Some of the islands of Indian Ocean were completely washed away.
  • Indira point in Andaman got completely submerged.
  • More than 10,000 people were killed and more than a lakh of houses were affected.
  • Coastal areas of Tamil Nadu. Kerala, Puducherry, Andhra Pradesh and the Andaman and Nicobar islands were worst affected.

Question 5.
Can such an event be predicted in advance?
Answer:
Earthquake cannot be predicted in advance but it is possible to give 3-4 hour notice of potential Tsunami. Such system are there in Pacific Ocean but not in Indian Ocean. Seismic activity and Tsunami threat is higher in the Pacific.

Question 6.
Why was the Tsunami of December 26, 2004 very devastating?
Answer:

  • The Tsunami that ravaged the South and South-east Asian coasts in December 2004 was the most devastating Tsunami in the last several hundred years.
  • The large damage caused to life and property was primarily a result of the following:
  • lack of monitoring,
  • the early warning systems, and
  • lack of knowledge among the coast dwellers of the Indian ocean.
  • The first indication that Tsunami is approaching was the rapid withdrawal of water from the coastal region.
  • It was followed by destructive wave.
  • When this happened on the coast, instead of people going to high ground, they started assembling at the coast to view the miracle.
  • It resulted in a large casualty of curious onlookers when the gigantic wave-tsunami struck.

Tides

Question 1.
What are tides?
Answer:
The rhythmic rise and fall of ocean water twice a day is called a tide. When water rises to its highest level and covers much of the ocean it is called high tide. During low tide the water falls to its lowest level and recedes from the shore.

Question 2.
Explain Spring and Neap Tides.
Answer:
During the full moon and new moon days, the sun, the moon and the earth are in the same liNe.

  • On this day the tides are highest.
  • These tides are called Spring Tides.
  • But when the moon is in its first and last quarter, the ocean waters get drawn in diagonally opposite direction by the gravitational pull of the sun and the earth.
  • It results in low tides.
  • These tides are called Neap Tides.

Question 3.
Describe the importance of tides to man.
Answer:

  • High tides help in navigation.
  • They raise the water level close to the shores.
  • This helps the ships to arrive at the harbour more easily.
  • The high tides also help in fishing.
  • Many more fish come closer to the shore during the high tides.
  • This enables fishermen to get a plentiful catch.
  • The rise and fall of water due to tides is used to generate electricity in some places like the gulf of Khambant.

Ocean Currents

Question 1.
What are Ocean currents?
Answer:
Ocean currents are streams of water flowing constantly on the ocean surface in definite directions. They may be warm or cold currents:

  • Warm currents originate near equator and move towards poles. They bring about warm temperatures over land surfaces, for example Gulf stream.
  • Cold currents originate near poles and move towards tropical or lower latitudes. They bring about coolness over land surfaces, for example Labrador current.

Question 2.
Explain the advantages and disadvantages of ocean currents to man.
Answer:
The ocean currents influence the temperature conditions of the coastal areas.

  • Warm currents increase the temperature over land surface.
  • The areas where warm and cold currents meet, provide the best fishing grounds of the world.
  • Seas Around Japan and the eastern coast of North America are such examples.
  • The areas where a warm and cold current meet, also experience foggy weather making it difficult for navigation.

Question 3.
Seas around Japan are good fishing ground but difficult for navigation. Give reasons.
Answer:
Cold and warm currents meet and create good fishing grounds around Japan and Eastern Coast of North America.

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CHAPTER -4 Air | CLASS 7TH | NCERT GEOGRAPHY IMPORTANT QUESTIONS & MCQS | EDUGROWN

Chapter - 4 Air

MCQs

Question 1.
Which gas released in the atmosphere creates a greenhouse effect trapping the heat?
(a) Carbon dioxide
(b) Oxygen
(c) Nitrogen
(d) All of these

Answer

Answer: (a) Carbon dioxide

Question 2.
Excess amount of CO2 is responsible for
(a) global cooling
(b) global warming
(c) both (a) and (b)
(d) none of these

Answer

Answer: (b) global warming

Question 3.
What are the important objects for survival of plants and animals?
(a) Rainfall
(b) Sun light
(c) Oxygen
(d) All of these

Answer

Answer: (d) All of these

Question 4.
Which one of the following gases is present in the atmosphere in the highest amount?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Lithium

Answer

Answer: (c) Nitrogen

Question 5.
Which gas is used by the green plants to make their food?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) None of these

Answer

Answer: (b) Carbon dioxide

Question 6.
Which is the important gas used by human beings for breathing?
(a) Nitrogen
(b) Carbon dioxide
(c) Oxygen
(d) Sodium chloride

Answer

Answer: (c) Oxygen

Question 7.
When the air is heated it becomes
(a) Lighter?
(b) Heavier?
(c) Colder?
(d) None of these

Answer

Answer: (a) Lighter?

Question 8.
What is the average height of the troposphere?
(a) 3 km
(b) 6 km
(c) 9 km
(d) 13 km

Answer

Answer: (d) 13 km

Question 9.
As we go up in troposphere layer of the atmosphere the pressure
(a) increases
(b) decreases
(c) no change
(d) all of these

Answer

Answer: (b) decreases

Question 10.
Which one of the following gases protects us from harmful sun’s rays?
(a) Ozone
(b) Nitrogen
(c) Carbon dioxide
(d) Oxygen

Answer

Answer: (a) Ozone

Question 11.
Which of the following are part of weather forecast in the newspapers?
(a) Temperature
(b) Humidity
(c) Time of Sunset
(d) All of These

Answer

Answer: (d) All of These

Question 12.
Which element of weather is measured in degree Celsius?
(a) Temperature
(b) Pressure
(c) Wind
(d) Gravity

Answer

Answer: (a) Temperature

Question 13.
The water boils at
(a) 10°C
(b) 50°C
(c) 75°C
(d) 100°C

Answer

Answer: (d) 100°C

Question 14.
Where is the air pressure highest?
(a) Moon
(b) Sea Level
(c) Stratosphere
(d) Exosphere

Answer

Answer: (b) Sea Level

Question 15.
What is very hot wind called?
(a) Loo
(b) Cool breeze
(c) Monsoon air
(d) Trade wind

Answer

Answer: (a) Loo

Question 16.
Which one of the following is a local wind?
(a) Sea breeze
(b) Trade wind
(c) Monsoon wind
(d) None of these

Answer

Answer: (a) Sea breeze

Question 17.
Rain, snow sleet or hail are the different forms of:
(a) Condensation
(b) Evaporation
(c) Precipitation
(d) All of these

Answer

Answer: (c) Precipitation

Match the contents of Column A with that of Column B

Column AColumn B
1. Temperature(a) Bacteria in soil
2. Pressure(b) Thermosphere
3. Seasonal wind(c) Barometer
4. Radio waves transmission(d) Thermometer
5. Nitrogen from air(e) Change directions in different seasons
Answer

Answer:

Column AColumn B
1. Temperature(d) Thermometer
2. Pressure(c) Barometer
3. Seasonal wind(e) Change directions in different seasons
4. Radio waves transmission(b) Thermosphere
5. Nitrogen from air(a) Bacteria in soil

Fill in the blanks with appropriate words:

1. Earth is surrounded by a blanket of air called ………….

Answer

Answer: atmosphere

2. Green plants produce …………. during photosynthesis.

Answer

Answer: oxygen

3. Increased volume of ………….. is affecting the earth’s weather and climate.

Answer

Answer: carbon dioxide

4. Ionosphere is the part of ……………

Answer

Answer: thermosphere

5. Amount of rainfall is measured by ………….

Answer

Answer: rain gauge

6. Insolation influences the distribution of …………….

Answer

Answer: temperature

State whether the given statements are true or false.

1. Hot air is dense and heavy and cold air is lighter and expands.

Answer

Answer: False

2. Without Greenhouse effect earth would have been too cold to live.

Answer

Answer: True

3. Ionosphere contains the ozone layer.

Answer

Answer: False

4. Helium and hydrogen float from exosphere into space.

Answer

Answer: True

5. Wind-vane shows the direction of wind.

Answer

Answer: True

6. Air moves from high pressure to low pressure.

Answer

Answer: True

Question 1.
Define the term atmosphere.
Answer:
Blanket of air surrounding the earth is known as the atmosphere.

Question 2.
How do all living beings depend on the atmosphere for their survival?
Answer:
All living beings depend on the atmosphere for their survival.

  • Atmosphere provides them the air they breathe.
  • It protects them from the harmful effects of the sun’s rays.
  • Without its protection, they would be baked alive by the heat of the sun during day and get frozen during night.

Question 3.
What is green house effect?
Answer:
Carbon dioxide in the atmosphere traps the heat radiated from the earth creating a green house effect. This makes the temperatures livable. Without this earth would have been too cold to live. But the increased emissions from vehicles and factories increases the temperature leading to global warming.

Question 4.
What is global warming? What is its affect?
Answer:
When the heat retained through greenhouse gas increases the temperature of the earth, it causes global warming:

  • The plants maintain the balance of gases. However this balance is upset by burning fuels such as coal, petroleum oil and large scale deforestation.
  • This rise in temperature causes the snow in coldest parts to melt.
  • As a result the sea level rises causing floods in the coastal areas.
  • This may bring changes in weather and climate leading to extinction of certain plants and animal species.

Composition of the Atmosphere

Question 1.
Name the two gases which influence the atmosphere to a great extent.
Answer:

  • Two gases such as carbon dioxide and ozone influence the atmosphere to a large extent.
  • Their percentage in the atmosphere is as under:
  • Carbon dioxide 0.03%
  • Ozone 0.00006%

Question 2.
Describe the composition of the atmosphere.
Answer:
Composition of the Atmosphere:

  • The air we inhale while breathing is actually a mixture of numerous gases.
  • Nitrogen and oxygen are two gases which make up the most of the atmosphere.
  • Carbon dioxide, helium, ozone, argon and hydrogen are found in lesser quantities.
  • Tiny dust particles are also present in the air.

Air Class 7 Extra Questions Geography Chapter 4 - 1

Question 3.
How is nitrogen present in atmosphere used by plants?
Answer:
Nitrogen is the most plentiful gas in the air.

  • Plants need nitrogen for their survival. They cannot take nitrogen directly from the air.
  • Bacteria in the soil or the roots fix nitrogen by changing its form so that plants can use it.

Question 4.
Which is the second most plentiful gas in the atmosphere?
Answer:
Oxygen is the second most plentiful gas in the atmosphere. Humans and animals use it for breathing. Green plants produce oxygen through photosynthesis and thus oxygen balance is maintained in air. This gets disturbed if we cut trees.

Question 5.
Explain how the oxygen and carbon dioxide balance is maintained in air?
Answer:
Green plants use carbon dioxide to make their food and during this process release oxygen:

  • Humans and animals release carbon dioxide and take oxygen from air.
  • The amount of carbon dioxide released by them is equal to amount used by plants
    to make their food. Hence a balance is maintained.
  • But now the excess of carbon dioxide is released by burning of fuels. The reduction in number of plants upset the balance of gases like carbon dioxide affecting earth’s weather and climate.

Question 6.
Explain the circulation of air in atmosphere.
Answer:
When air is heated it expands, becomes lighter and rises up:

  • Cold air is dense, so, it sinks down.
  • When hot air rises up, cold air from surrounding areas fills in the gap.
  • This is the process of circulation of air.

NOTES: News reports around the world

  • Due to burning of fuels and cutting of trees C02 level are increasing
  • Globed sunscreen thinned
  • Warning unstoppable
  • It can bring back Jurassic era.

Structure of the Atmosphere

Question 1.
Discuss the structure of the atmosphere.
Answer:
Structure of the Atmosphere:
The atmosphere is divided into five layers according to height, starting from the earth’s surface.
They are

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere

Question 2.
Which is most important layer of the atmosphere?
Answer:
Troposphere

  • Troposphere is the important layer of the atmosphere.
  • Its average height is 13 km.
  • It is 8 kilometres on the poles and 18 kilometres on the equator.
  • The air (which living beings breathe) exists here.
  • All the weather phenomena like winds, rainfall, fog, hailstorm etc. occur in this layer.

Air Class 7 Extra Questions Geography Chapter 4 - 2

Question 3.
Which layer the most suitable conditions for flying aeroplanes?
Answer:
Stratosphere:

  • The stratosphere lies above the troposphere.
  • It extends up to a height of 50 km.
  • This layer is almost free from clouds.
  • No weather phenomenon occurs in this layer making conditions most ideal for flying aeroplanes.
  • Stratosphere contains a layer of ozone gas.
  • It protects living beings from the harmful effects of the sun rays.

Question 4.
What is the third layer of atmosphere?
Answer:
Mesosphere:

  • Mesosphere is the third layer of the atmosphere.
  • It lies above the stratosphere.
  • It extends up to a height of 80 km.
  • Meteorites bum up in this layer on entering from the space.

Question 5.
Briefly write about thermosphere?
Answer:
Thermosphere

  • In thermosphere temperature rises very rapidly with increasing height.
  • Ionosphere is a part of this layer.
  • It extends between 80 and 400 km.
  • This layer helps in radio transmission.
  • Radio waves transmitted from the earth are reflected back to the earth by this layer.

Question 6.
Which is the uppermost layer of the atmosphere?
Answer:
Exosphere

  • The uppermost layer of the atmosphere is known as exosphere.
  • This layer has very thin air.
  • Light gases like helium and hydrogen float into the space from here.

Weather and Climate

NOTES: Many questions are asked about days conditions especially on an important day like cricket match or wedding etc. Questions like’ will it rain or will it be sunny; etc. basically are related to day’s weather. Such questions are not asked about climate

Question 1.
What is weather?
Answer:
Weather is the day to day condition of the atmosphere. For example a sunny day or rainy day. Weather is like a control knob of climate.

Question 2.
Define the term climate.
Answer:
The sum total of all weather conditions prevailing over large area for a longer period of time is called climate.

Question 3.
What is the difference between weather and climate?
Answer:
Weather is hour-hour conditions of atmosphere like hot humid weather may make us irritable but same day breezy or pleasant evening may make one cheerful. We have hot or cold climate over a period of few months.
Therefore we have daily forecast of weather and long term predictions of climatic conditions.

Question 4.
Name different types of weather measuring instruments.
Answer:
Thermometer – measures temperature
Barometer – measures atmospheric pressure
Rain gauge – measures amount of rainfall
Wind wane – shows direction of wind

Temperature

Question 1.
What is temperature?
Answer:

  • The degree of hotness or coldness is called the temperature.
  • Temperature changes not only between day and night but also from season to season.

Question 2.
What is insolation?
Answer:
Insolation is the incoming solar energy intercepted by the earth. It influences the distribution of temperature.

Question 3.
Why are poles covered with snow?
Answer:
The amount of insolation decreases from equator towards poles, therefore the temperature also reduces. But if the earth’s temperature rises too high, it would be too warm to raise crops.

Question 4.
Why cities are more hotter than villages?
Answer:
The temperature in cities is much higher than that of villages because the concrete and metals in the buildings and the tar and asphalt in the roads gets heated throughout the day and absorbs heat. This heat is released at night hence there is the difference in the temperature.
The crowded high rise buildings trap the warm air and thus raise the temperature of the cities.

Air Pressure

Question 1.
Why don’t we feel the air pressure?
Answer:
The air above us presses us from all sides with great force but we do not feel it. This happens because our body exerts a counter pressure.

Question 2.
Define the term air pressure.
Answer:
Air pressure is the pressure exerted by the weight of air on the earth’s surface. As we move in the upper layers of atmosphere, the pressure falls rapidly.

Question 3.
How does air pressure vary from equator to poles and from surface to heights?
Answer:
Variation in Distribution of Pressure

  • As we go up the layers of atmosphere, the pressure falls rapidly.
  • The air pressure is highest at sea level
  • It decreases with increase in height.
  • Horizontally the distribution of air pressure is influenced by temperature of air at a given place.

Question 4.
What is the relation between temperature and pressure?
Answer:
Distribution of air pressure is influenced by the temperature of the area:

  • Where temperature is high the air gets heated and rises. This creates a low pressure area.
  • Low pressure is associated with cloudy skies and wet weather.
  • In areas with low temperature, the air is cold and heavy so, it sinks down. This creates a high pressure area.
  • High pressure is associated with clear and sunny skies.
  • Air always moves from high pressure to low pressure areas.

Question 5.
Why do Astronauts wear a protective gear on moon?
Answer:
Astronauts wear a protective suit filled with air when they go to moon because the counter pressure exerted by the body would make the blood vessels burst.

Wind

Question 1.
Define the term wind. Explain with examples.
Answer:
The movement of air from high pressure to low pressure areas is called wind. For example wind blows dry leaves or strong wind uproots trees. Blowing smoke or dust is the work of wind. Strong wind makes it difficult to walk or hold umbrella.

Question 2.
Which are the three components of cyclone?
Answer:
Three components of cyclone are wind velocity, rain and tidal surge.

Question 3.
What are the various categories of wind? Explain with a diagram.
Answer:
Winds can be broadly divided into three types:

  • Permanent winds – which blow constantly throughout the year in a particular direction.
    Example, easterlies and westerlies.
  • Seasonal winds – which change directions in different seasons. For example, monsoon winds.
  • Local winds – blow only during a particular period of the day or the year in a small area. For example, land or sea breeze, or loo.

Air Class 7 Extra Questions Geography Chapter 4 - 3
Question 4.
What is Cyclone?
Answer:
A powerful and destructive storm with very high speed winds that moving in circular motion around an area of low pressure.

Question 5.
Describe the fury of cyclone taking example of ‘Super cyclone’ of Odisha.
Answer:
Odisha on eastern sea coast of India is prone to cyclones originating in Bay of Bengal.

  • Odisha was hit by cyclone on 17th-18th October 1999 and again on 29th October.
  • Cyclone originated as a ‘depression’ in the Gulf of Thailand near Port Blair.
  • It moved in northwest direction on 25th October and intensified into super cyclone and hit Odisha.
  • Wind speed was upto 260 km/hr which lasted for 36 hours.
  • Trees were uprooted kutcha houses, roof tops industrial sheds etc blown away.
  • Power supply and communication lines damaged.
  • Continues rains flooded the major rivers. Tidal waves swept 20 km of inland areas including cities of Bhubaneshwar and Cuttack and destructed 28 coastal towns.
  • 7-10 m high tidal waves caused damage to paddy crops, vegetables fruits and agricultural land turned infertile due to salination.
  • 13 million people were affected. Livestock was killed.
  • Plantations of teak, sal, bamboo, mangrove forests of Paradeep and Konark disappeared.

Moisture

Question 1.
What is humidity?
Answer:
When water evaporates from different water bodies and land it turns into water vapours or moisture. Moisture in air at any time is known as humidity.

Question 2.
What is a humid day?
Answer:
A day when air is full of water vapour is called a humid day. With the air getting warmer its capacity to hold moisture increases so it becomes more humid. On such days clothes takes longer to dry and even body sweat does not evaporate easily.

Question 3.
How are clouds formed? How do clouds cause precipitation?
Answer:

  • When water vapour rises, it starts cooling.
  • Water vapour condenses which results in formation of droplets of water.
  • These droplets hanging in the air above are called clouds.
  • Clouds are masses of these water droplets.
  • When these droplets of water become too heavy to float in the air, they come down as precipitation.

Question 4.
Why do jet planes leaves a white trail behind them?
Answer:
Jet planes flying in the sky leave a white trail behind them,

  • The moisture from their engines condenses.
  • We see trails of this condensed moisture for sometime when there is no air movement to disturb it.
  • These trails of condensed moisture are actually clouds.

Question 5.
What are different forms of precipitations?
Answer:
Different forms of precipitations are: dew, rainfall, hail, snowfall, fog, sleet.

Question 6.
What is rain? What is its importance?
Answer:
Precipitation in liquid form is called rain. Most of the ground water comes from rainwater. It is important for survival of plants and animals. It brings fresh water to earth.
If rainfall is more or trees are cut on hills, rain water can cause flooding in low lying areas. If it is less than water scarcity or drought may occur.

Question 7.
What are the types of rainfall?
Answer:
Based on the mechanism rainfall can be of three types: Convectional, Orographic or Cyclonic.

Objective type Questions

Question 1.
Fill in the blanks with appropriate words:
1. Earth is surrounded by a blanket of air called ………………..
2. Green plants produce ……………………… during photosynthesis.
3. Increased volume of ……………………. is affecting the earth’s weather and climate.
4. Ionosphere is the part of ……………………….
5. Amount of rainfall is measured by ………………………
6. Insolation influences the distribution of ……………………
Answer:
1. atmosphere
2. oxygen
3. carbon dioxide
4. thermosphere
5. rain gauge
6. temperature

Question 2.
State whether the given statements are true or false.
1. Hot air is dense and heavy and cold air is lighter and expands.
2. Without Green house effect earth would have been too cold to live.
3. Ionosphere contains the ozone layer.
4. Helium and hydrogen float from exosphere into space.
5. Wind – vane shows the direction of wind.
6. Air moves from high pressure to low pressure.
Answer:
1. False
2. True
3 False
4. True
5. True
6. True.

Question 3.
Match the contents of Column A with that of Column B
Air Class 7 Extra Questions Geography Chapter 4 - 4
Answer:
1. (d)
2. (c)
3. (e)
4. (b)
5. (a)

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