Last updated on December 9th, 2023 at 09:02 pm
MCQ on Class 7 Science Waste Water Story
What term describes wastewater released by homes, industries, and other human activities?
a) Drinking water
b) Clean water
c) Rainwater
d) Sewage
Answer: d) Sewage
Which of the following is a major source of water-borne diseases due to contaminated water?
a) Freshwater lakes
b) Ocean water
c) Sewage treatment plants
d) Polluted rivers
Answer: c) Sewage treatment plants
What process is used to remove large rubbish objects from wastewater, such as rags, sticks, and cans?
a) Biological process
b) Chemical process
c) Physical process (Screening)
d) Sedimentation process
Answer: c) Physical process (Screening)
During wastewater treatment, which component settles to the bottom of the first sedimentation tank?
a) Oil and grease
b) Nitrogen
c) Sludge
d) Oxygen
Answer: c) Sludge
What is the purpose of passing compressed air bubbles through wastewater in the aeration tank?
a) To remove sand and grit
b) To remove oil and grease
c) To increase bacterial activity
d) To disinfect the water
Answer: c) To increase bacterial activity
The primary cause of the increase in water-borne diseases such as cholera and typhoid is what?
a) Lack of oxygen in water
b) Overuse of chlorine
c) Contaminated water and poor sanitation
d) Excessive rainfall
Answer: c) Contaminated water and poor sanitation
What is the purpose of a manhole in the sewage system?
a) To release purified water
b) To provide access for inspection and cleaning
c) To dispose of chemicals
d) To create aeration in wastewater
Answer: b) To provide access for inspection and cleaning