Understanding Candle Flame Properties

The video tutorial explains the concept of combustion and the structure of a candle flame. It highlights the differences between the flames of LPG and a candle, noting the clean blue flame of LPG and the yellow luminous flame of a candle. The structure of a candle flame is divided into three zones: innermost, middle, and outermost. Each zone has distinct characteristics, such as temperature and combustion completeness. Activities demonstrate the presence of unburned wax vapors in the innermost zone, unburned carbon particles in the middle zone, and the high temperature of the outermost zone.

What is the color of the flame produced by LPG?

• Yellow

• Blue

• Red

• Green

Which substance does not vaporize and hence does not produce a flame?

• Kerosene

• Charcoal

• Candle wax

• LPG

How many regions are there in a candle flame?

• Five

• Four

• Two

• Three

What is the color of the flame in the middle zone of a candle?

• Green

• Yellow

• Red

• Blue

What does the innermost zone of a candle flame consist of?

• Burned wax vapors

• Unburned wax vapors

• Oxygen

• Carbon particles

What happens when an ignited matchstick is brought near the end of the glass tube in the innermost zone activity?

• Nothing happens

• The glass tube melts

• The wax vapors catch fire

• The flame goes out

What is formed on the glass slide when it is introduced into the middle zone of the flame?

• A red ring

• A blue ring

• A blackish ring

• A white ring

What does the middle zone of the flame consist of?

• Burned wax vapors

• Unburned carbon particles

• Oxygen

• Water vapor

Which part of the flame is the hottest?

• Outermost zone

• Middle zone

• Innermost zone

• None of the above

What happens to the copper wire when it is held just inside the flame for about 30 seconds?

• It melts

• It turns red-hot

• It turns blue

• It remains unchanged