If $25\%$ of the total incident radiation $Q = 500 \, J$ is absorbed and $105 \, cal$ is transmitted,calculate the percentage of reflected power.

For athermanous substances,the coefficient of transmission is

As compared to a person with white skin,a person with black skin will experience:

For a perfectly black body,the coefficient of emission (emissivity) is:

Inside a closed furnace held at a temperature of $400\, K,$ we have a black body. $A$ hole of area $10\, cm^2$ is opened in the furnace so that sunlight starts falling on the black body. The intensity of sunlight is $2000\, W/m^2.$ In the steady state:

If between wavelength $\lambda$ and $\lambda + d\lambda$,$e_\lambda$ and $a_\lambda$ are the emissive and absorptive powers of a body,respectively,and $E_\lambda$ is the emissive power of a perfectly black body,then according to Kirchhoff's law,which of the following is true?