For an opaque body,the coefficient of transmission is:

If $e_\lambda$ and $a_\lambda$ are the emissive power and absorptive power of a body respectively,and $E_\lambda$ is the emissive power of a perfectly black body,what is the relation according to Kirchhoff's law?

Shown below are the black body radiation curves at temperatures $T_1$ and $T_2$ $(T_2 > T_1)$. Which of the following plots is correct?

Surface temperature of the sun is of the order of $K$.

Consider black body radiation in a cubical box at absolute temperature $T$. If the length of each side of the box is doubled and the temperature of the walls of the box and that of the radiation is halved, then the total energy

Which of the following is best close to an ideal black body?