Question

1. Write about the different types of combustion.
2. In a candle flame what is the colour of
- innermost zone
- middle zone
- outerzone
In which zone of a candle flame-
partial combustion of fuel takes place
- complete combustion of fuel takes place.
3. Define the calorific value of a fuel. Name the unit in which the calorific value of a fuel is expressed.
4. It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain.
5. Draw a well labelled diagram of candle flame.

Please tell it's argent....... ​

Answer 1

Answer:

1.The three important types of combustion:

1. Rapid Combustion

2. Spontaneous Combustion

3. Explosive Combustion

2.In a Candle flame, the colour of

• innermost zone is black.
• middle zone colour is yellow
• outer zone colour is blue.

3. The yellow colour region which is the bright part of the flame is the middle zone. It is moderately hot and partial combustion of fuel takes place

outer zone is blue in colour. It is the hottest part of the flame, because complete combustion takes place in this zone.

4. Calorific value of fuel:

Calorific value is the amount of energy released or produced when 1 kg of fuel burns or any other substance is burnt in the presence of oxygen and the products of combustion are cooled to STP. Its SI unit is kJ/kg.

5. Green leaves have a lot of chlorophyll and moisture in them. This moisture does not allow them to catch fire easily when a heap of green leaves are burnt. However, dry leaves have no moisture or water content in them. Therefore, the heap of dry leaves catch fire easily.