NCERT Solutions for Class 7 Science Chapter 16 Water A Precious Resource
NCERT solutions for class 7 science chapter 16 water a precious resource exercise
- Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T/F)
(b) Water shortage is a problem faced only by people living in rural areas. (T/F)
(c) Water from rivers is the only source for irrigation in the fields. (T/F)
(d) Rain is the ultimate source of water. (T/F)
Answer:
(a) True
(b) False
(c) False
(d) True
- Explain how groundwater is recharged?
Answer:
The rainwater and water from water bodies get accumulated in the aquifer deep underground. Then there are some rocks which prevent further sinking of water.
In this way, groundwater is recharged.
- There are ten tubewells in a lane of fifty houses. What could be the long term impact on the water table?
Answer:
If they will draw water from the ground more than the rechargeable amount for the long term then the water table will go down.
- You have been asked to maintain a garden. How will you minimise the use of water?
Answer:
Drip irrigation method will be very efficient in this case as water is required in good quantity for the plants.
So we can save a lot of water by this method.
- Explain the factors responsible for the depletion of water table.
Answer:
The main factors responsible for the depletion of the water table are:-
(i) Increasing population so higher consumption.
(ii) Increasing industries
(iii) Agricultural activities
- Fill in the blanks with the appropriate answers:
- (a) People obtain groundwater through________ and ________.
- (b) Three forms of water are ________, ________ and ________.
- (c) The water bearing layer of the earth is ________.
- (d) The process of water seepage into the ground is called ________.
Answer:
(a) tube wells and hand pumps
(b) ice, water and vapour
(c) aquifer
(d) infiltration
- Which one of the following is not responsible for water shortage?
(i) Rapid growth of industries
(ii) Increasing population
(iii) Heavy rainfall
(iv) Mismanagement of water resources
Answer:
Heavy rainfall cannot be responsible for water shortage. Instead if stored properly it can increase the groundwater level.
- Choose the correct option. The total water
(i) in the lakes and rivers of the world remains constant.
(ii) under the ground remains constant.
(iii) in the seas and oceans of the world remains constant.
(iv) of the world remains constant.
Answer:
The total water of the world remains constant.
- Make a sketch showing groundwater and water table. Label it.
Answer:
The required sketch is shown below:-