Combustion and Flame

What is produced when combustible substances vapourises during burning?
1. Flame
2. Explosion
3. Both of these
4. None of these
The process of cutting trees in large number:
1. Aforestation
2. Contsruction
3. Deforestation
4. Destruction
Rise of temperature of the atmosphere of the earth due to combustion of fuels is called_____
1. Global warming
2. Greenhouse effect
3. Acid rain
4. Carbon dioxide effect
The lowest temperature at which substance catches fire is called its______
1. Combusting temperature
2. Ideal temperature
3. Ignition temperature
4. Heating temperature
Why it is difficult to burn heap of green leaves but dry leaves catches fire easily? (NCERT Textbook)
1. Because its ignition temperature is lower than of dry leaves.
2. Because its ignition temperature is higher than of dry leaves.
3. Because ignition temperature of dry leaves is higher than that of green leaves.
4. Bwcause both have same ignition temperature.
What is the formula for calculating calorific value of the fuel?
1. Calorific value = $\frac{h e a t p r o d u c e d}{a m o u n t o f f u e l}$
2. Caloric value = $\sqrt{\frac{h e a t p r o d u c e d}{a m o u n t o f f u e l}}$
3. Calorific value = $h e a t p r o d u c e d + a m o u n t o f f u e l$
4. Calorific value = $h e a t p r o d u c e d \times a m o u n t o f f u e l$
Which process can be called as of combustion?
1. Which produces only heat but not light when combusting.
2. Which produces only light but not heat while combusting.
3. Which produces both heat and light, while combusting.
4. Which produces sound while combusting.
Three essential requiremnts for producing fire are_______
1. Fuel, air and water.
2. Fuel, heat and water.
3. Fuel, air and non-combustible substance.
4. Fuel, air and heat.
Identify the hottest zone:
1. Luminous Zone
2. Dark Zone
3. Non-Luminous Zone
4. Candle wax
The process of combustion in which large amount of gases are evolved with the production of tremendous amount of heat, light and sound is_____
1. Rapid combustion
2. Spontaneous combustion
3. Explosion
4. Flame