Question

What type of fuels?
(a) Burns with a flame
(b) Burns without a flame

Answer 1

We all understand the term ‘fuel’. It is the substance that can undergo chemical and nuclear change to produce the energy that can be converted into useful work. This is known as fuel. We have to tell the examples of the fuel that burns with a flame and without a flame.

Complete answer: We are using different types of fuel in our everyday life. For example- cow dung, petrol, diesel, compressed natural gas (CNG) etc.
To answer the given question, we need to understand about the fuel and its classification. A fuel is a substance which undergoes a chemical and nuclear change to produce the energy for doing useful work. A fuel is classified into two sources of energy i.e. renewable sources of energy and non- renewable sources of energy.
Renewable sources of energy- It is the source of energy which is consumed once that can be renewed by a biogeochemical cycle occurring in nature. For example- wind energy, solar energy etc.
Non- renewable sources of energy- It is the source of energy which is consumed once that cannot be renewed by biogeochemical processes occurring in nature. For example- Coal and petroleum. It takes millions of years for its formation.
Now, we all have seen the burning of a candle and the burning of a coal. Have you ever noticed the difference between them? Yes, there is a difference between a candle burning with a flame and coal burns without a flame.
The fuel that evaporates on heating burns with a flame, example- LPG, candle etc. whereas fuel that does not evaporate on heating burns without a flame, example- Petrol, diesel etc.

Note:
Remember that fuel is a substance that undergoes combustion. It is said to be combustible. Also, combustion is a chemical process in which a substance reacts with oxygen to give off heat. The fuel may be solid, liquid or gas. Also, one interesting thing is that food acts as fuel for our body.