STD-4, CHAPTER-8: WATER SCARCITY AND CONSERVATION OF WATER, EXERCISE Q/As

 

A.     FILL IN THE BLANKS.

1.      The earth is known as a ______ planet.

Ans: Blue

2.      ______ and ______ are two major natural sources of water.

Ans: Rain and Snow

3.      Setting-up of factories cause a ______ in the level of underground water.

Ans: decrease

4.      Cutting of trees in the forests causes a ______ in rainfall.

Ans: decrease

5.      Use of water sprinkler for irrigation reduces the _____ of water.

Ans: wastage

B.      MATCH THE FOLLOWING:

1.      Cutting of trees in the forests                             (a) water conservation

2.      Collecting rain water for                                    (b) dam

day-to-day use                        

3.      Proper utilisation of water                                  (c) deforestation

and avoiding its wastage                                        

4.      A method of preserving large                             (d) rain water harvesting

quantity of water and checking

floods                             

      Ans:

1.      Cutting of trees in the forests                             (c) deforestation

2.      Collecting rain water for                                    (d) rain water harvesting

day-to-day use                        

3.      Proper utilisation of water                                  (a) water conservation

and avoiding its wastage                                        

4.      A method of preserving large                             (b) dam

quantity of water and checking

floods                             

 

C.      TICK THE CORRECT OPTION.

1.      Two major natural sources of water are –

(a)   Rain and wells                                      

(b)   Snow and rivers

(c)    Rain and snow                 

(d)   Ground water and rivers

Ans: Rain and snow

2.      Planting of more trees will help in –

(a)   Reducing the ground water level                                      

(b)   Setting-up more factories

(c)    deforestation                

(d)   increasing the rainfall

      Ans: increasing the rainfall

3.      We can avoid wastage of water by –

(a)   Using water sprinkler                                      

(b)   Over-irrigation

(c)    Washing our car with a jet of water                 

(d)   Allowing water to leak from taps

      Ans: Using water sprinkler

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

1.      How much of the surface of earth is covered by water?

Ans: Three-fourth of the surface of earth is covered by water.

2.      Name three sources of fresh water.

Ans: Rivers, streams and lakes are the sources of fresh water.

3.      State the effect of deforestation on rainfall.

Ans: Deforestation results in a decrease in rainfall.

4.      State two reasons that are leading to cleaning of forests.

Ans: : i) Forests are being cleared, for building houses and factories.

ii) Also, people cut trees for earning money by selling the wood of trees.

5.      State one utility of dams.

Ans: Dams preserve a large quantity of water.

E.      ANSWER THE FOLLOWING QUESTIONS.

1.      State three factors that are responsible for water scarcity.

Ans: Three factors that are responsible for water scarcity are, i) Population,

         ii) Deforestation and iii) Setting-up of factories.

2.      How does setting-up of factories affect the ground water level?

Ans: i) The factories need a large quantity of water. So, they use underground water.

ii) Due to shortage of rainfall, underground water does not get filled up again as much as it is used.

iii) This has led to a sharp decrease in the level of underground water.

3.      State two ways to do rain-water harvesting.

Ans: i) Rain water can be collected in large underground tanks from where it seeps slowly into the ground.

ii) Rain water may also be collected in overhead tanks and used for daily needs.

4.      How should the fields be irrigated to reduce wastage of water?

Ans: i) Over-irrigation of fields should be checked.

ii) Water sprinkler should be used for irrigation. This reduces the wastage of water.

5.      State any three ways of conserving water at home.

Ans: We can conserve water at home by adopting the following measures.

i) Turn off the tap after using it.

ii) Use a mug and bucket to take bath instead of a shower.

iii) Get the leaking pipes and taps repaired immediately.