Which types of resources of energy are coal, petroleum and natural gas?

1. conventional sources
2. non-renewable sources
3. non-conventional sources
4. Both (a) and (b).

…………… coal has …………… per cent of carbon content and is the most preferred variety of coal.

1. Lignite, 40
2. Peat, 50
3. Anthracite, 90
4. Bituminous, 80

Bituminous coal is also known as …………… .

1. coking coal
2. Peat
3. Steam oven
4. Gas stove

Anthracite is ideal for domestic use as it is smokeless and has high …………… value.

1. industrial
2. calorific
3. volatile
4. demand