MCQs

Question 1.
Which one is a process in which water changes into vapours in atmosphere?
(a) Evaporation
(b) transpiration
(c) Precipitation
(d) condensation

Question 2.
Potable water is
(a) ocean water
(b) groundwater at selected places
(c) river water
(d) ponds water

Question 3.
Which is not a part of water cycle?
(a) Cloud formation
(b) Rain
(c) Drinking by animals
(d) Sun

Question 4.
Which is a result of condensation of water vapours?
(a) Rain
(b) Snowfall
(c) Hail
(d) Tiny water droplets

Question 5.
Which one is the purest form of water?
(a) River water
(b) Groundwater
(c) Rainwater
(d) Ocean water

Question 6.
Circulation of water between ocean and land is known as
(a) water cycle
(b) rain cycle
(c) water management
(d) water harvesting

Question 7.
The percentage of water in potato is
(a) 88
(b) 75
(c) 90
(d) 95

Question 8.
Out of these, which is not a source of surface water?
(a) rain water
(b) river and lake water
(c) Spring water
(d) sea water

Question 9.
Boiling point of water is
(a) 100°C
(c) 101°C
(b) 99°C
(d) 102°C

Question 10.
Plants release large amount of water vapour into the atmosphere by the process called
(a) evaporation
(b) condensation
(c) precipitation
(d) transpiration

Match the following items given in Column A with that in Column B:

Fill in the blanks with appropriate words:

1. ………………. is needed for drinking, bathing, washing our clothes and many more functions.

2. Large part of the earth is covered by……………………

3. The water in the oceans is very ……………. in taste.

4. Ice, water and ………………….. are the three states of same material.

5. Water vapours get continuously added to atmosphere due to evaporation and ………………

6. The process of conversion of vapours into liuid is known as ………………………

Answer

Answer: transpiration

Important Questions

VERY SHORT ANSWER TYPE QUESTIONS

1. Write the sources of water on the earth.
Ans:  Sources of water on the earth are:
Seas, Oceans, Rivers, Springs, Tubewells, etc.

2. In which forms, water exists on the earth?
Ans: Water exists on the earth in all three physical forms: ice, water and water vapour.

3. What is transpiration?
Ans: Loss of water in the form of water vapour through stomata of leaves is called transpiration.

4. How are the clouds formed?
Ans: Clouds are formed by the condensation of water vapour at high altitude.

5. What is meant by the conservation of water?
Ans: Careful, economical and wise use of water and avoiding the wastage of water is called conservation of water.

SHORT ANSWER TYPE QUESTIONS
1. Mention two main functions of water for living organisms.
Ans: Two main functions of water for living organisms are:
1. Water is essential for the germination of seeds, growth of plants and in photosynthesis.
2. Water is used for the transportation of people and goods.

2. Why is ocean water not suitable for domestic use?
Ans: Sea and ocean water contains large amounts of various salts. It is due to these salts the ocean water is salty and cannot be used for drinking, washing and for irrigation purposes.

3. Why does the water split on the floor disappear after some time?
Ans:  Due to evaporation the water split is changed into water vapour. So it disappears after some time.

4. How does heavy rain affect us?
Ans: Heavy rains may cause:
1. A rise of water level in dams, rivers, lakes, etc.
2. Waterlogging and floods.
3. Floods cause damage to property, crops and animals.

5. How does the failure of rainfall affect people on the earth?
Ans: The failure of rainfall can cause the following:
1.The soil becomes dry.
2. Water level in rivers, lakes, dams, etc. may fall. Ponds and canals may even dry up.
3. The ground water level falls.

6. Name two processes responsible for the formation of clouds.
Ans:  Evaporation and transpiration.

There are 4 containers A, B, C and D with same amount of water in each. Answer the following based on them.
(a) Name the container in which water will evaporate faster than all others.
(b) Name the container in which water will evaporate very slowly.
Give reason for your answer.
Ans.
(a) C – More is the exposed surface area, more will be evaporation of water.
(b) B – As it is closed, no evaporation takes place.

8. During winters why do we see more fog in close areas where there are lots of .trees?
Ans:  Due to lots of trees, air at that place contains much more water vapour during winters. These vapour condense on dust or smoke particles forming thick fog.

LONG ANSWER TYPE QUESTIONS
1. What is meant by conservation of water? Suggest three methods to conserve water.
Ans:  Careful and economical use of water and avoiding its wastage is called conservation of water.
Suggestions for conserving water:

1. Use only the required quantity of water.
2. Trees and forests help in causing rainfall. So to conserve water, we should plant more and more trees.
3. By collecting rainwater in tanks, ponds or by constructing check dams.

2. What is rainwater harvesting? Describe the method of rainwater harvesting.
Ans: Rainwater harvesting is the collection of rainwater and storing for future use. In this system rainwater in collected from the rooftops by means of pipes into storage tank for later use.
Methods of Rainwater Harvesting:

1. Rooftop rainwater harvesting. In this system, the rainwater from the rooftop is collected in a storage tank, through pipes.
2. Another method, a big pit is dug near house for collecting rainwater. This pit is filled with different layers of bricks, coarse gravels and sand or granite pieces