Question

incandescent reason in candle flame is
1 non luminous zone
2 luminous zone
3 dark zone

Answer 1

Because due to luminous zone

Answer 2

Incandescent reason in candle flame is due to Luminous Zone .

Explanation:

A flame consist of three zones :
---> Innermost Zone
---> Middle Zone
---> Outermost Zone.

The three zones of a  flame have different colours and different temperature.

The Innermost Zone is the coldest part[Dark zone ] of the flame.

The Middle zone of a flame is yellow.
It is bright and luminous [light giving].

Incandescent means giving light on heating.

So here the fuel vapours burn partially and produces carbon particles. These carbon particles becomes white hot and emit light.

So, it is the glow of hot carbon particles which makes the middle zone of flame luminous.