What is a perfect black body GCSE?
An object that is good at absorbing radiation is also a good emitter , so a perfect black body would be the best possible emitter of radiation.
Features of a perfect black body.
Stars are considered to be black bodies because they are very good emitters of most wavelengths in the electromagnetic spectrum ..
Does Black have a high or low albedo?
Since 30% of the sun’s energy is reflected by the entire earth, the earth has an average albedo of . 30. Generally, dark surfaces have a low albedo and light surfaces have a high albedo. For example, in summer the black asphalt road is scorching hot.
What is perfect black body radiation?
Blackbody, in physics, a surface that absorbs all radiant energy falling on it. The term arises because incident visible light will be absorbed rather than reflected, and therefore the surface will appear black. The concept of such a perfect absorber of energy is extremely useful in the study of radiation phenomena.
What is albedo value?
Albedo is a non-dimensional, unitless quantity that indicates how well a surface reflects solar energy. … Albedo commonly refers to the “whiteness” of a surface, with 0 meaning black and 1 meaning white. A value of 0 means the surface is a “perfect absorber” that absorbs all incoming energy.
Why is a star a black body?
Stars are considered to be black bodies because they are very good emitters of most wavelengths in the electromagnetic spectrum . This suggests that stars also absorb most wavelengths. Whilst there are a few wavelengths that stars do not absorb or emit, this figure is very low, so they can be treated as black bodies.
Why is a black body a perfect emitter?
The name “black body” is given because it absorbs radiation in all frequencies, not because it only absorbs: a black body can emit black-body radiation. … It is an ideal emitter: at every frequency, it emits as much or more thermal radiative energy as any other body at the same temperature.