CBSE Basic Concepts and Assignment for Class XII Biology - Environmental Issues . Based on CBSE and CCE guidelines. The students should read these basic concepts to gain perfection which will help him to get more marks in CBSE examination.
VSA (1 MARK)
1. Why should the velocity of air between the plates of an electrostatic precipitator be low?
2. PM2.5 is responsible for causing greatest harm to human health. What is it? How is it harmful?
3. What is the noise level that can cause permanent impairment of hearing ability of human beings?
4. Why was the Montreal Protocol signed?
5. Jhum cultivation has been in practice from earlier days, but its considered more problematic these days. Why?
6. A radiation causes ageing of skin, skin cancer, and inflamation of cornea called snow blindness. It also damages DNA. Name the radiation.
SA-II (2 MARKS)
7. Landfills are not much a solution for getting rid of solid wastes. Why?
8. Electrostatic precipitator can remove over 99% particulate matter present in exhaust from a thermal power plant. How?
9. Why is a scrubber used? Which spray is used on exhaust gases passing through a scrubber?
10. There is a sharp decline in dissolved oxygen downstream from the point of sewage discharge. Why? What are its adverse effects?
11. Catalytic converters use expensive metals as catalysts.
(a) Name the metals generally used.
(b) What precaution should be observed while using catalytic converter.
12. What are e-wastes? Why are they creating more problem in developing countries in comparision to developed countries?
13. Water logging and salinity are some of the problems that have come in the wake of Green revolution. How does water logging create problems of salinity?
14. What is the relationship between BOD, mcro-organisms and amount of biodegradable matter?
Please refer to attached file for CBSE Class 12 Biology - Environmental Issues