Which of the following is/are the characteristic(s) of a good fuel?

All of these

The correct answer is option 4. All of these.

Sources of heat energy for domestic and industrial purposes are mainly wood, charcoal, petrol, kerosene etc. These substances are called fuels.

A good fuel is one which is readily available.

It is cheap.

It burns easily in air at a moderate rate.

It produces a large amount of heat.

It does not leave behind any undersirable substances.