Question

which of the following is the characteristic of a black body
a) A peretect absorber but imperfect radiator
b) a perfect radiator but am imperfect absorber
c) a perfect radiator and a perfect absorbed
d) a perfect conductor
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Answer 1

Answer:

a perfect radiator and a perfect absorbed

Answer 2

Answer:

The answer to this question is option (C), a perfect radiator and a perfect absorber

Explanation:

Concept:

A black body is an ideal physical body that absorbs all incident electromagnetic radiation, no matter what the frequency is .

Now here the point to note is that a black body in thermal equilibrium i.e. at a constant temperature, also emits electromagnetic black-body radiation because to main the temperature of the body at constant temperature , it must emit radiation as well otherwise only absorbing the EM radiation will increase the body temperature.

Therefore an ideal black body in thermal equilibrium is a perfect radiator as well as a perfect absorber.

Hence option (C) is the correct option.