CBSE Class VII, Science (NCERT)
Sample questions with their Solutions (as per latest CCE scheme of examinations of CBSE)
Important Short Type Questions with Solutions
Q.1: Which decade has been decided for action on “Water for Life”?
Solution: It is 2005 - 2015.
Q.2: By which name the toilets in which human excreta are treated by earthworms is called?
Solution: Vermi-processing toilet.
Q.3: Fill in the blanks:
- _______ is generated in homes, industries, agricultural fields and in other human activities. This is called _______.
- Sewage is a liquid waste which causes ______ and ____ pollution.
- Wastewater is treated in _______ treatment plant.
- By-products of wastewater treatment are ______ and _______.
- ________ of water can be removed by boiling it or treating it with washing soda.
- Cleaning of waste water is commonly known as ________.
Solution: a. wastewater, sewage. b. water, soil. c. sewage. d. sludge, biogas. e. hardness. f. sewage treatment.
Q.4: What is ‘Sanitation’?
Solution: The proper disposal of sewage and garbage from the houses and other sources like industries etc. is called ‘Sanitation’.
Q.5: What is ‘Chlorination’?
Solution: It is the process of adding bleaching powder to water. Water can be made suitable for drinking purpose by chlorination.
Important Long Type Questions with Solutions
Q.1: What are different methods to make water potable (fit for drinking)?
Solution: We use different methods in our homes to make water potable. Water obtained from the source is filtered before use. Those who depend on wells for the supply of water pot a few crystals of potassium permanganate into the well. Bleaching powder chlorine tablets are also used to make water fit for drinking. Now-a-days machines are available for water purification in which water is passed through carbon filter, ultra-violet ray or through Reverse Osmosis process.