Pollution of Air and Water Exam Questions Class 8 Science

Exam Questions Class 8

Please refer to the Pollution of Air and Water Notes Class 8 Science given below. These revision notes have been designed as per the latest NCERT, CBSE, and KVS books issued for the current academic year. Students will be able to understand the entire chapter in your class 8 th Science book. We have provided chapter-wise Notes for Class 8 Science as per the latest examination pattern.

Revision Notes Chapter 18 Pollution of Air and Water Class 8 Science

Students of Class 8 Science will be able to revise the entire chapter and also learn all important concepts based on the topic-wise notes given below. Our best teachers for Grade 8 have prepared these to help you get better marks in upcoming examinations. These revision notes cover all important topics given in this chapter.

Question. What is the “3R” principle?
Answer :
There are 3R’s to save the environment from the harmful effects of non-biodegradable wastes such as plastics. The three R’s stand for Reduce, Reuse and Recycle.
1) Reduce: This means that we should use the resources judiciously and check their misuse.
2) Recycle: Recycle means that we should collect the used and discarded plastic, paper, glass and metal items and recycle this material to make required things instead of synthesizing fresh plastic, paper, glass or metal.
3) Reuse: We should use the same things again. For example envelopes can be used by reversing them

Question. Write a short note on CFC.
Answer : 
Chloro Fluoro Carbon

Question. What do mean by air pollution? Name any two air pollutants.
Answer : 
When air is contaminated by unwanted substances which have a harmful effect on both the living and the non-living, it is called air pollution. The substances that pollute air are called air pollutants.
Name of pollutants: Carbon dioxide and Carbon Monoxide.

Question. What is global warming?
Answer : 
The greenhouse effect is the cause of global warming, i.e. overall increase in the temperature of the Earth. When solar radiation reaches the Earth, some radiations are absorbed by the Earth and then released back to the atmosphere. Greenhouse gases like methane, CO2 and water vapour present into the atmosphere trap these radiations and do not allow the heat to leave.
This helps our planet in keeping warm and thus helps in human survival. However, an indiscriminate increase in level of greenhouse gases, it can lead to an excessive increase in the Earth’s temperature leading to global warming.

Question. How can we control air pollution?
Answer : 
1. By planting more number of trees as trees take up carbon dioxide and release oxygen.
2. We should use CNG; instead of petrol and diesel in automobiles.
3. Avoid unnecessary usage of vehicles.
4. Try using public transport more.
5. Natural resources like solar energy, tidal energy, etc. should be used.

Question. What are problems caused by global warming?
Answer : 
1) Global warming increases temperature of earth.
2) It increases in level of water in rivers and oceans resulting in frequent floods in surrounding areas and submerging coastal cities.
3) It disturbs water cycle and rain pattern.