NCERT Solutions for Class 7th Science

Chapter 16 – WATER: A PRECIOUS RESOURCE

(Complete Downloadable Chapter Solution PDF file is at the bottom of the page)

 

Q.1      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)

Ans    (a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the                    world. (T)

           (b) Water shortage is a problem faced only by people living in rural areas. (F)

           Correct: Water shortage is a problem faced by both people living in rural and in urban areas.

           (c) Water from rivers is the only source for irrigation in the fields. (F)

           Correct: Source of irrigation can be river, canals, tube wells etc.

           (d) Rain is the ultimate source of water. (F)

Q.2      Explain how groundwater is recharged?

Ans     The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the             empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called             infiltration. By this process the groundwater gets recharged.

Q.3      There are ten tube wells in a lane of fifty houses. What could be the long term impact on the water table?

Q.4      You have been asked to maintain a garden. How will you minimise the use of water?

Q.5      Explain the factors responsible for the depletion of water table.

Ans     Factors responsible for the depletion of water table are:

            1) Increasing Population: Increasing population creates demand for construction of houses, shops,                         offices, roads and pavements. This decreases the open areas like parks, and playgrounds. This, in turn,                 decreases the seepage of rainwater into the ground.

            2) Increasing Industries: Water is used by all the industries at various stages. The number of 

Q.6      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 ________.

Ans     (a) People obtain groundwater through _wells_ and _tube-wells_.

            (b) Three forms of water are _solid (ice)_, _liquid (water)_ and _gas (vapour)_.

Q.7      Which one of the following is not responsbile for water shortage?

(i) Rapid growth of industries

(ii) Increasing population

(iii) Heavy rainfall

(iv) Mismanagement of water resources

Q.8      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.

Q.9      Make a sketch showing groundwater and water table. Label it.