When you introduce a glass plate into the luminous zone of a candle flame for a few seconds, the observation is as shown in figure (b). What does the observation indicate?

Options

A. Deposition of burnt `CO_2` particles present in the air around the flame.
B. Deposition of unburnt carbon particles in the luminous zone of the flame.
C. Deposition of molten wax.
D. All of these.

Answer

B

Explanation

Luminous zone, is the yellow zone, where incomplete combustion takes place because in this zone, the combustible vapours do not get sufficient oxygen to burn. Thus when a glass plate is introduced in luminous zone some unburnt carbon particles remain and cause black deposition.