Combustion and Flame Science - Combustion and Flame

Shyam was cooking potato curry on a chulha. To his surprise, he observed that the copper vessel was getting blackened from outside. It may

Which one among the following is considered as the cleanest fuel?

On placing an inverted tumbler over a burning candle, the flame extinguishes after some time. This is because of non-availability of

If a person's clothes catch fire, the best way to extinguish the fire is to

The substance that does not burn with flame is

The substances which vaporise during ____________ give flame.

The substances which gave very ____________ Ignition temperature and can easily catch fire with a flame are called ____________ substances.

A ____________ process in which a substance reacts with ____________ to give off heat is called combustion.

____________ gas is a promoter of combustion.

____________ fuel is cheap, readily available and cause less pollution.

Boojho wants to separate the following materials as combustible and non-combustible. Can you help him? Charcoal, chalk, stone, iron rod, copper coin, straw, cardboard, glass, paper, candle, wood.

What do you understand by fuel efficiency ?

The calorific values of petrol and CNG are 45000 kJ/kg and 50000 kJ/kg, respectively. If you have vehicle which can run on petrol as well as CNG, which fuel will you prefer and why ?

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

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

Air is necessary for combustion.

Spontaneous combustion takes place in the absence of external heat.

LPG fire is an inflammable substance.

Middle zone is the hottest zone of a flame.

Water is the best extinguisher for fires involving electrical equipment.

In severe cold weather, Mohan's family burnt wood in the room during the night keeping the windows close After some time, they felt suffocation. Mohan Immediately opened the windows and get relief.
(i) What did actually happen ?
(ii) What values are associated with Mohan ?

A factory was started near a village. Suddenly, villagers started feeling the presence of irritating vapours in the village. Mr. Lalit Jain was school teacher in that village. He noted that the cases of headache, chest pain, cough, dryness of throat and breathing problems are increasing among the villagers. He blamed the emission from the chimney of the factory for such problems. He gave the written complain in behalf of all the villagers.
Read the given passage and answer the following questions.
(i) Explain what could have happened in the village.
(ii) What values are shown by Mr. Lalit Jain ?

Forest fire produces a lot of air pollution. Write in brief about the reasons of forest fires.

Give two examples each for a solid, liquid and gaseous fuel along with some important uses.

Why should we never sleep in a room with burning or smouldering coal fire ?

Why is it important to know the telephone number of the fire service in your area ?

We have read that the Sun produces it's own heat and light. Is it also some kind of combustion ?

We were told that food is a fuel for our body. Why ?

Anu wants to boil water quickly in a test tube. On observing the different zones of the flame, she is not able to decide which zone of the flame will be best for boiling water quickly. Help her in this activity.

Match the following for the flame of a candle.

Column I	Column II (Zone)	Column III (colour)
A. Hottest part	1. Innermost zone of unburnt wax vapours	(x) Blue
B. Moderately hot	2. Middle zone of partial combustion	(y) Black
C. Least hot	3. Outer zone of complete combustion	(z) Yellow