Question

Which of the following is the characteristic of a black body?

(a) A perfect absorber but an imperfect radiator

(b) A perfect radiator but an imperfect absorber

(c) A perfect radiator and a perfect absorber

(d) A perfect conductor

I have been asked this question by my college director while I was bunking the class.

The doubt is from Compton Effect topic in chapter Quantum Physics of Engineering Physics I

Answer 1

Right option is (c) A perfect radiator and a perfect absorber

The best I can explain: When the radiations are made to pass through a black body, it undergoes multiple reflections and is completely absorbed. When it is placed in a temperature bath of fixed temperature, the heat radiations will come out. Thus a black body is a perfect absorber and a perfect reflector.