Which zone is the hottest part in a candle flame?
Innermost zone
Middle zone
Outermost zone
Wax zone
Which one is the best fire extinguisher?
SO2
CO2
NO2
O2
When the LPG gas stove at home gives a yellow flame, it implies that
The fuel undergoes partial combustion
The fuel undergoes complete combustion
The fuel on burning gives yellow burnt particles
None of these
Which is a fuel?
Wood
Carbon monoxide
Nitrogen
Oxygen
The inflammable substances are
i) Hydrogen ii) Phosphorous iii) water iv) coke
(i ) only
(i) & (ii)
i, ii, iv
(i) & (iv)
Which of the following statements is correct?
Any substance that can burn is an inflammable substance
Spontaneous cumbustion starts at room temperature
During an explosion, a large amount of acid is produced.
Water is useful in putting out all fires.
The process of burning a substance in the presence of air with the evolution of heat is called:
distillation
carbonisation
combustion
refining
An ideal fuel is
Of high calorific value
Of moderate ignition temperature
Economical
All of these
A flame always points upwards because
Gases produced in flame are cold
Gases produced in flame are hot
Hot gases are lighter and hence rise up
Both b & c
Which of the following has the highest calorific value?
Petrol
Coke
Natural gas
Kerosene
