Question

Compared to a person with white skin another person with dark skin will experience:
A) Less heat and more cold
B) More heat and more cold
C) More heat and less cold
D) Less heat and less cold

Answer 1

Hint: All bodies (objects) emit and absorb types of electromagnetic radiation. They do this regardless of their temperature and colour. The intensity of radiation increases as the body gets hotter and the body or the object gives out more radiation in a given time. The type of radiation emitted depends on the temperature of the radiating body. Whether a person experiences heat or cold and to what extent depends on the degree of absorption and emission of heat by the body.

Complete solution:
White and shiny reflecting surfaces are the worst absorbers and they reflect all visible light wavelengths. Poor absorbers of heat are also poor emitters and do not emit radiation as quickly as darker colours. This is the reason why radiators in homes are usually painted white.
When the body is black, all the light that hits the surface is absorbed. An object that is a good absorber of radiation is also a good emitter; therefore a perfect black body would be the best possible emitter of radiation.
From the above argument, we can state that a black body is a better absorber of heat and a better emitter as well. This implies that a person with dark skin will experience more heat and more cold.
The inverse of this is also possible. This means that a person with white skin will experience less heat and less cold as compared to a person with dark skin.

Hence option (B) is the correct answer.

Note: There are no known bodies that are perfectly absorbing or emitting, this means that not all radiation directed at it would be absorbed or bounced off. Some objects, however, bear close resemblance to this ideal behaviour and are referred to as black bodies. A perfect black body is a theoretical object. It would have these properties:
It would absorb radiations of all frequencies falling on it.
It would not reflect or transmit radiations of any frequency.
Be careful in choosing the correct option; here we compared a person with dark skin to a person with white skin, hence the suitable option was (B). If we were to compare a person with white skin to a person with dark skin, the correct option would have been (D).