Correct Option
The correct option is (c).
Explanation
A candle flame consists of three distinct zones based on the availability of oxygen and the extent of combustion: the innermost zone (dark), the middle zone (luminous), and the outer zone (non-luminous).
Statement-wise Analysis:
- Statement 1 is Incorrect. The middle zone is the luminous zone of the flame, not the non-luminous zone. The non-luminous zone refers to the outermost part of the flame where complete combustion occurs, usually appearing blue.
- Statement 2 is Correct. The middle zone is characterized by a limited supply of oxygen. Consequently, the wax vapours undergo partial combustion rather than complete combustion.
- Statement 3 is Correct. Due to partial combustion, unburnt carbon particles are produced. These particles become hot and emit light, giving the middle zone a characteristic yellow colour.
Key Takeaway:
The middle zone of a candle flame is the zone of partial combustion, is luminous (yellow), and is moderately hot compared to the outer zone.