NCERT Class VIII Science Solutions: Chapter 6-Combustion and Flame Part 2

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Question 8:

The substance expected to have the highest ignition temperature out of the following is

  1. Kerosene

  2. Petrol

  3. Coal

  4. Alcohol

Answer: C

Question 9:

Choose the correct statement about inflammable substances from the following.

They have:

  1. Low ignition temperature and cannot catch fire easily.

  2. High ignition temperature and can catch fire easily.

  3. Low ignition temperature and can catch fire easily.

  4. High ignition temperature and cannot catch fire easily.

Answer: C

Image of Inflammable substance

Inflammable Substance

Image of Inflammable substance

Question 10:

Choose the incorrect statement from the following.

Forest fires are usually due to:

  1. Carelessness of humans

  2. Heat of sun

  3. Cutting of trees

  4. Lightning strike

Answer: C

Question 11:

The calorific value of a fuel is expressed in a unit called

  1. Kilojoule per liter

  2. Kilogram per milliliter

  3. Kilojoule per gram

  4. Kilojoule per kilogram

Answer: D

Question 12:

In villages, people use wood as fuel because:

  1. It is considered to be an ideal fuel.

  2. Of its easy availability and low cost.

  3. It is environment friendly.

  4. It catches fire easily.

Answer: B

Question 13:

Which among the following is considered as the cleanest fuel?

  1. Cow dung cake

  2. Petrol

  3. Kerosene

  4. Hydrogen gas

Answer: D

Question 14:

Choose the incorrect statement from the following. A good fuel is one which:

  1. Is readily available.

  2. Produces a large amount of heat.

  3. Leaves behind many undesirable substances.

  4. Burns easily in air at a moderate rate.

Answer: C

Question 15:

Shyam was cooking potato curry on a . To his surprise he observed that the copper vessel was getting blackened from outside. It may be due to:

  1. Proper combustion of fuel.

  2. Improper cooking of potato curry.

  3. Improper combustion of the fuel.

  4. Burning of copper vessel.

Answer: C