Give one example of each combustible and non-combustible substance.

What is the fuel of our body?

Write the products which are formed when magnesium burns with oxygen.

If we cut off the supply of air for combustion of a substance, what will happen?

At which temperature, a substance catches fire and starts burning?

Water is not suitable for firs involving oil and petrol. Why?

Why we cover the fire (like a blanket) to extinguish fire?

Write phosphorus burns in air at room temperature on its own. Which type of combustion is it?

If the supply of oxygen is not sufficient, will the fuels burn completely?

LPG stoves burn with which colour of flame? Why?

A candle consists of unburnt wax vapours. Which zone is this?

Fuels can be in solid or liquid state only. Is it correct?

Write the unit of calorific value.

Burning of wood is harmful for human beings. How?

Write the causes of global warming.

Name the most common fire extinguisher.

How many zones are there in a flame?

How does pouring water extinguish a fire?

Write an example of gaseous fuel.

Carbon dioxide causes acid rain. Is it correct?

What gives a pollution free environment when burnt?

Define the word ‘explosion’.

What is meant by rapid combustion? Give two examples.

Explain how the use of CNG in automobiles has reduced pollution in cities?

Give two examples each of (i) solid fuels and (ii) liquid fuels.

State the disadvantages of burning wood as a fuel.

Water can boil in a paper cup. How?

Why does charcoal not produce a flame?

Define calorific value.

How luminous flames differ non-luminous flames?

Explain how burning of fuels such as coal, petrol and diesel leads to acid rain. Give the harmful effects of acid rain.

With the help of an experiment, show that air is necessary for burning of a candle.

Write the conditions necessary for combustion.

Draw a diagram showing zone containing very hot carbon particles.