What is blackbody ?

Question

Your Defination of Blackbody

Answer 1

Hello!
Every object absorbs/reflect/emit radiation, which wavelength/frequency depends, firstly, on the type of material (type of atoms/structure) and, secondly, the the temperature.

Black Body is a material that absorbs all the wavelengths of radiation that fall onto it, not only the visible light, but all the electromagnetic spectrum. Although, above 700 Kelvin it starts to emit radiation, starting from red (1000 K) to blue (10.000).

Answer 2

It's anything that absorbs radiant energy at all wavelengths and radiates a spectrum that depends upon its temperature in accord with the Rayleigh-Jeans distribution.

Doug