Question

A white surface is a
A. Good absorber
B. Poor absorber
C. Good reflector
D. Both B and C

Answer 1

Hint: Remember that heat is always transferred from a hotter object to a cooler object, hence, the hotter body will emit more radiation than a cooler body. The black surface will emit more radiation than that of the white surface.

Complete answer:
When it comes to radiation, the surface of an object plays an important role.
The black matte surfaces absorb the radiation and as they become warm after absorbing the radiation they start emitting the radiation. Therefore, a black surface is a good absorber and a good emitter. It can be seen in daily life as the person wearing a black t-shirt becomes warm because it absorbs the sunlight.
On the other hand, light surfaces or white surfaces do not absorb radiation. If they will not absorb radiation then they will not be able to emit any radiation. Thus, the white surface is a poor absorber and poor emitter.
Also, if the white surface does not absorb radiation then they will reflect the radiation. Therefore, white surfaces are good reflectors.
Hence, a white surface is a poor absorber and a good reflector.

So, the correct answer is “Option D”.

Note:
In hot countries, people often paint their houses with white color as it keeps their houses cool because white surfaces reflect the heat into the atmosphere.
Also, we can see an example of a teapot. The shiny surface of the pot does not absorb the heat inside it, hence it acts as a poor emitter, as a result, the teapot remains hot for longer.