Describe a candle flame.

Important Questions on Combustion and Fuels

MEDIUM

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q C

Mention five factors (apart from easy availability at a reasonable price) which should be considered while choosing a fuel.

EASY

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q D

A log of wood attains the ignition temperature _____ than wood shavings do. (Faster/ Slower)

MEDIUM

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q D

In the liquid state, hydrogen is used as a fuel in _____. (train / satellite / bus / spacecraft)

HARD

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q D

Insert the remark ‘good’, ‘better’, ‘best’ or ‘unsuitable’ for the fuels mentioned in the following table.

Fuel	Calorific value (in $\mathrm{k}\mathrm{J}/\mathrm{g}$)	Ignition temperature (in ${}^{\mathrm{o}}\mathrm{C}$)	Remark
$\mathrm{A}$	$100$	$5$
$\mathrm{B}$	$80$	$70$
$\mathrm{C}$	$70$	$80$
$\mathrm{D}$	$60$	$90$

EASY

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q D

Gaseous fuels are _____ than solid and liquid fuels. (better/worse)

MEDIUM

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q E

Water is used to extinguish a fire because it

MEDIUM

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q E

Which among the following fuels has the highest calorific value?

MEDIUM

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 7 - Combustion and Fuels>Exercises>Q E

Which of the following is not derived from a fossil fuel?