Dispersion of light and temperature

[nilic1]

In a question about dispersion using an equilateral prism, three blackened bulb thermometers were used. One was placed above the red light, one on the green light and the last one below the violet light.

The question was ...

Give 2 reasons why the highest temperature would be recorded above the red light.

My guess is...

Reason 1: There is the presence of infrared radiation which causes a temperature increase.
Reason 2: ?


Any help please?

Regards.

 

[nilic1]

Over 80 views but no answer. I am doubting the validity of this question at this point?