The total radiative power emitted by spherical blackbody with radius R and temperature T is P. If the radius if doubled and the temperature is halved then the radiative power will be -

Options

A. `P/4`
B. `P/2`
C. 2P
D. 4P

Answer

A

Explanation

`P=sigma AT^4 = sigma xx 4 pi R^2 xx T^4`
`implies P. = sigma xx 4 pi (2P)^2 xx(T/2)^4`
`implies P. = sigma xx 4 pi R^2 T^4 xx 4 xx (1)/(16) implies P. =P/4`