NCERT Class VIII Science Solutions: Chapter 6-Combustion and Flame Part 7

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Question 37:

Forest fire produces a lot of air pollution. Write in brief about the reasons of forest fires.

Answer:

  1. At high temperature, sometimes dry grass catches fire which spreads throughout the forest.

  2. Camp fire may also be a reason.

  3. Human negligence.

  4. Lightening.

Question 38:

Complete the crossword Fig with the help of the clues:

Result for Complete the crossword (Q)

Complete the Crossword (Q)

Result for Complete the crossword (Q)

Across:

1. Non-metal which catches fire if exposed to air (10)

3. The lowest temperature at which a substance catches fire is called its __________ temperature. (8)

5. The most common fire extinguisher. (5)

Down:

2. A chemical process in which a substance reacts with oxygen to give off heat. (10)

4. Petrol is used as a __________ in automobiles. (4)

6. It is as hard as stone and black in colour. (4)

Answer:

Result for Complete the crossword (A)

Complete the Crossword (A)

Result for Complete the crossword (A)

1. Non-metal which catches fire if exposed to air - Phosphorus

3. The lowest temperature at which a substance catches fire is called its __________ temperature - Ignition

5. The most common fire extinguisher - water

Down:

2. A chemical process in which a substance reacts with oxygen to give off heat - Combustion

4. Petrol is used as a __________ in automobiles - Fuel

6. It is as hard as stone and black in colour - Coal