Question

In accordance with Kirchhoff's law for a black body radiation, which one is wrong?
Bad absorber is a bad emitter
Bad reflector is a good emitter Bad emitter is a good absorber
Bad reflector is a gooabsorber​

Answer 1

The incorrect choice is "Bad emitter is a good absorber".

• A good absorber is a bad reflector because it will absorb all waves and reflect none.
• Being a bad emitter means the black body is not able to radiate more energy.
• So good absorbers can radiate more energy hence they will be good emitters.
• Therefore statement 1, 2 and 4 are correct because they mean that a good absorber will be a good emitter but a bad reflector.