The Class 7 is an important year in a student’s life and Science is one of the subjects that require dedication, hard work, and practice. It’s a subject where you can score well if you are well-versed with the concepts, remember the important formulas and solving methods, and have done an ample amount of practice. Worry not! Home Revise is here to make your Class 7 journey even easier. It’s essential for students to have the right study material and notes to prepare for their board examinations, and through Home Revise, you can cover all the fundamental topics in the subject and the complete NCERT Class 7 Science Book syllabus.
Exercise Questions
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 of irrigation in the fields. (T/F)
(d) Rain is the ultimate source of water. (T/F)
Solution:
a) True
b) False
c) False
d) False
2. Explain how groundwater is recharged.
Solution:
The rainwater and water from other sources, such as rivers and ponds, seep through the soil and fill the empty spaces and cracks deep below the ground. The process of seeping water into the ground is called infiltration. The groundwater thus gets recharged by this process.
3. There are ten tube wells in a lane of fifty houses. What could be the long-term impact on the water table?
Solution:
If ten tube wells in a lane of fifty houses are situated, the groundwater will get used for domestic purposes. This results in the depletion of the groundwater level, and the water table goes down.
4. You have been asked to maintain a garden. How will you minimise the use of water?
Solution:
We can reduce the usage of water for gardening by adopting the drip irrigation method. In this method, water will reach the roots of the plant drop by drop, which will reduce the wastage of water.
5. Explain the factors responsible for the depletion of the water table.
Solution:
The factors responsible for the depletion of the water table are as follows:
Increase in population: Increase in population leads to increased demand for water for domestic and drinking purposes. This reduces the water table.
Industrialisation: Industries need a lot of water for manufacturing purposes. This reduces the water table.
Agriculture: Agriculture requires a lot of water for growing crops; this results in the depletion of the water table.
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 ________.
Solution:
(a) People obtain groundwater through tube wells and hand pumps .
(b) Three forms of water are ice, water and vapour.
(c) The water-bearing layer of the earth is Hydrosphere .
(d) The process of water seepage into the ground is called infiltration .
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
Solution:
The answer is option (iii) Heavy rainfall.
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.
Solution:
The answer is option (iv) of the world remains constant.
9. Make a sketch showing the groundwater and water table. Label them.
Solution:
