Class 8 Combustion-Flame
Combustion and Flame
Multiple Choice Questions (MCQs)
- An example of spontaneous combustion is :
(b) burning of yellow phosphorus
(c) the burning of magnesium
- The gas used in cooking cylinders is :
- The hottest part of the flame is :
(a) luminous zone
(b) central zone
(c) non-luminous zone
(d) none of these
- One of the followings is not a combustible substance. which one?
- The gas formed by incomplete combustion of carbon is :
(a) carbon monoxide
(b) carbon dioxide
(c) sulphur dioxide
(d) water vapour
- Acid rain can be caused by the burning of :
- Which of the following fuels is expected to leave a residue upon burning?
- Which of these will extinguish a fire?
(a) Removing the combustible substance
(b) Reducing the temperature of combustible substance below the ignition temperature
(c) Cutting off the air supply
(d) All of these.
- Water is used to extinguish the fire because of it:
(a) raises the ignition temperature of the burning substance
(b) lowers the ignition temperature of the burning substance
(c) cools the burning substance to a temperature below its ignition temperature
(d) conducts heat
- Which among the following fuels has the highest calorific value?
- Which of the following is not derived from a fossil fuel?
- Which of the following statement is not correct about carbon dioxide acting as a
fire extinguisher for electrical fires?
(a) It is heavier than air
(b) It is lighter than air
(c) It is not combustible
(d) It does not support combustion
- Which of the following fuels has the lowest calorific value?
- A heap of green leaves is lying in one corner of a park. The green leaves in
the heap burn with difficulty because :
(a) They contain a tough material called cellulose.
(b) They contain a lot of water
(c) They contain a green pigment chlorophyll.
(d) They do not get sufficient oxygen for burning.