Question

The colour of the flame in luminous zone is:
A) Blue
B) Red
C) Yellow
D) Black

Answer 1

Hint Firstly we should be clear that what exactly is the luminous zone and what colour is of the zone. Now we know that the colour is yellow because of the obtained temperature. This colour is because of its temperature. This is to produce enough soot to be luminous.

Complete solution:
Firstly we should be aware that the question is regarding the flame showing nature of the luminous zone.Now we have to apply a specific step by step approach towards finding the proper colour of the obtained flame in the luminous zone and the objects and the flame involved.
The correct flame that is obtained in the luminous zone is of the yellow colour.
Now, the flame is of the colour of yellow. This colour is because of its temperature. This is to produce enough soot to be luminous. Now the flame is operated at a lower temperature than its efficient heating flame (see Bunsen burner). The given colour of simple incandescence is due to black-body radiation and the frequency of the flame.
Therefore, option (C) is correct.

Note: A Bunsen burner, named after Robert Bunsen, is a kind of gas burner used as laboratory equipment; it produces a single open gas flame, and is used for heating, sterilization, and combustion. The gas can be natural gas (which is mainly methane) or a liquefied petroleum gas, such as propane, butane, or a mixture.