Page 78 - Science Class 08

4. Rus ng of iron is an example of slow combus on.
5. Fire caused by short circuit can be put out by using carbon tetrachloride.

6. The region of the flame which undergoes the process of incomplete combus on
is called non-luminous zone.

7. Environmental pollu on is caused due to excessive use of fuels.
8. Global warming is caused due to excessive accumula on of CO in the atmosphere.
2
D. Very short answer ques ons.

1. What do you mean by combus on?
2. Give any five examples of combus ble substances.
3. What do you mean by spontaneous combus on?
4. On what principle does soda-acid ex nguisher work?

5. Why should we not use water to put out the fire caused by electricity?
6. What is the luminous zone of the flame of a candle?
7. What are the effects of burning of fuel on environment?

8. What is acid rain?
E. Short answer ques ons.
1. Which things are needed for burning?
2. What is a combus ble substance?

3. How many types of combus on are there?
4. Define flame.
5. Describe global warming.

F. Long answer ques ons.
1. Why gaps are le between the pieces of coal in a chulha?
2. Write the difference between spontaneous and rapid combus on?
3. Why is foam ex nguisher used to put out the fire caused due to oil?

4. Explain about the different parts of a flame.
5. How is pollu on caused due to burning of fuels?

Project
Project ActivityActivityActivity
Project
Project Activity
1. Find out the number and types of fire ex nguishers available in your homes and school. Write
a report on how your school is well-prepared in case of a fire in the school.

2. Write a report on the precau ons one should take while using LPG.
3. Visit a fire sta on of your area and study the working of soda-acid fire ex nguisher. In what
way do these firemen work to ex nguish fire? Write a brief report about it.

HOTSTSTS
HO
HO
HOTS
A. Why does a flame always point upwards?
B. Why is it easier to burn dry leaves, but not green leave?

78 Science-8