Question
The temperature of the black body increases from T to 2T. The factor by which the rate of emission will increase, is?
4
2
16
8
Solution
C.
16
The total electromagnetic energy radiated by a body at absolute temperature T is proportional to its size, its ability to radiate (called emissivity) and most importantly to its temperature.
For a body, which is a perfect radiator, the energy emitted per unit time (H) is given by,
H = A σ T4
And this relation first obtained experimentally but Stefan and later proved theoretically by Boltzmann law and later known as Stefan- Boltzmann law
According to Stefan's law for radiated energy
E ∝ T4
