A small cavity of diameter 2 mm whose tempe_rature is 3000K acts as a black body. calculate the intensity of radiation emitted by it. If the temperature of the surroundings is J00K, then calculate the rate of radiant heat emitted to the surroundings.

Explanation

Given, `d=2xx10^(-13),T=3xx10^3K`
`A=(pid^4)/4=(3.142xx(2xx10^(-3))^2)/4=3.142xx10^(-6)m^2`
The intensity of the radiation emitted`=Asigma^(4)=3.142xx10^(-6)xx5.67xx5.67xx10^(-8)xx(3xx10^(3))^4`
`=1443xx10^(-2)=14.43Wm^(-2)`