Why is a black body a perfect absorber?

A blackbody allows all incident radiation to pass into it (no reflected energy) and internally absorbs all the incident radiation (no energy transmitted through the body). This is true for radiation of all wavelengths and for all angles of incidence. Hence the blackbody is a perfect absorber for all incident radiation.

Is a black hole a perfect blackbody?

Since radiation incident on the black hole is absorbed, the black hole must emit an equal amount to maintain detailed balance. The black hole acts as a perfect blackbody radiating at this temperature.

What is meant by perfect blackbody?

A body which absorbs all the radiant energy incident upon it and reflects or transmits none is called a perfectly black body. It absorbs all incident energy.

What is blackbody why it is not possible to achieve a perfect blackbody?

Since no object is a perfect absorber, no object will exhibit a perfect black body spectrum but it is there underlying and readings you take.

Is it essential that perfectly black body should appear black define perfect black body?

No, it is not necessary that all black coloured object should be considered as black bodies. For example , if we take a black surface which is highly polished, it will not behave as a perfect black body . On the other hand, the sun, which is a shining hot sphere, behaves as a perfect black body.

Do Blackbodies absorb or emit?

A black body is an idealized object that absorbs all electromagnetic radiation it comes in contact with. It then emits thermal radiation in a continuous spectrum according to its temperature. Stars behave approximately like blackbodies, and this concept explains why there are different colors of stars.

How did Stephen Hawking discover black holes?

In 1971, Stephen Hawking proposed the area theorem, which set off a series of fundamental insights about black hole mechanics. Hawking eventually squared the two ideas in 1974, showing that black holes could have entropy and emit radiation over very long timescales if their quantum effects were taken into account.

Why are good absorbers good emitters?

Therefore, the body emits radiation to lose energy and return to thermal equilibrium. Therefore if a body absorbs more energy, it must also lose more energy to maintain its temperature. This shows that good absorbers must also be good emitters.

Is there such thing as a perfect blackbody?

Blackbody radiation, sometimes called cavity radiation, refers to the behavior of a system that absorbs all radiation that is incident upon it and then re-radiates energy. While there’s no such thing as a perfect blackbody, most solid objects are sufficiently close to being a blackbody that they can be treated as one.