Black body is an object that absorbs all electromagnatic radiation that falls on it. (it is an idealization).
Some examples are: * Carbon in Graphite form absorbs 97% of incident radiation.
* A large cavity with a small hole is the closest thing to a blàck body. eg: a pin hole
* Stars are approximately black bòdy.
Black Body Radiation
When a black bòdy is heated it emits black bòdy radiation.
Blàck Body Radiation is of all wavelengths. The radiation is characteristic of the radiating system.
Radiation is supposed at thermal equilibrium with the wall of the container.