EVENTS
CONVENT H.SCHOOL
11/02/2021
CLASS-7 SLOT-2
Science
Chapter-16
A Precious
Crop
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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. (True)
(b) Water shortage is a problem faced only by people living
in rural areas. (False)
(c) Water from rivers is the only source for irrigation in
the fields. (False)
(d) Rain is the ultimate source of water. (True)
Q.2. Explain how groundwater is
recharged.
Ans. The groundwater gets recharged through the process of
infiltration. Infiltration means seeping of water from rivers and lakes into
the empty spaces and cracks deep below the ground.
Q.3.There are ten tubewells in a
lane of fifty houses. What could be the long-term impact on the water table?
Ans.The effect on the water table depends on the
replenishment of underground water. Only five families will share a tubewell,
the water used for daily domestic purposes will not effect the water table. But
if there is shortage of rains, the water used by the family will not
replenished and water table will fall down.
Q.4.You have been asked to maintain
a garden. How will you minimise the use of water? „
Ans.To minimise the wastage of water we will use the drip
irrigation which throws the water at the base of plants. We will check the
leakages in the water pipes and arrange small pits for rainwater harvesting.
The collected rainwater will be used later.
Q.5.Explain the factors responsible
for the depletion of water table.
Ans.Various factors responsible for the depletion of water
table are:
(i) Increased population: Demand of water has been
increased by the increased population. As the number of humans increase, the
consumption of water also increases.
(ii) Increasing industries: All industries need water. As
the number of human population increase, the number of industries are also
increased which definitely increases the consumption of water.
(iii) Lack of water conservation techniques: Main source of
water on earth and for the underground water is rain. The water of the rain, if
conserved can increase the ground water level. But this is not done due to lack
of water conservative techniques.
Q.6.Fill in the blanks with the
appropriate answers: .
(a) People obtain groundwater through wells and hand
pumps
(b) Three forms of water are solid, and liquid, gas.
(c) The water bearing layer of the earth is aquifer.
(d) The process of water seepage into the ground is called infiltration.
Q.7.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
Ans.(iii) heavy rainfall
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.
Ans.(iv) of the world remains constant.
Q.9.Make a sketch shoyving
groundwater and water table. Label it.
Ans
