$A$ body of area $1\, cm^2$ is heated to a temperature $1000\, K$. The amount of energy radiated by the body in $1\, second$ is .......... $Joule$ (Stefan's constant $\sigma = 5.67 \times 10^{-8}\, W\, m^{-2}K^{-4}$)

Two bodies $A$ and $B$ have emissivities of $0.01$ and $0.81$ respectively. The outer surface areas of both bodies are the same. Both bodies emit total radiant power at the same rate. The wavelength $\lambda_B$ corresponding to the maximum spectral radiance for body $B$ is $1.0 \mu m$. If the temperature of body $A$ is $5802 \ K$,then the temperature of body $B$ is .... $K$.

The cooling rate of a sphere at $600\,K$ in an external environment of $200\,K$ is $R$. When the temperature of the sphere is reduced to $400\,K$,the cooling rate of the sphere becomes:

The ratio of radiant energies radiated per unit surface area by two bodies is $16 : 1$. The temperature of the hotter body is $1000 \ K$. Then,the temperature of the colder body will be ....... $K$.

$A$ solid maintained at $t_{1}^{\circ} C$ is kept in an evacuated chamber at temperature $t_{2}^{\circ} C$ $(t_{2} > t_{1})$. The rate of heat absorbed by the body is proportional to

The Sun emits electromagnetic energy at a rate of $3.9 \times 10^{25} \ W$. Its radius is $6.96 \times 10^8 \ m$. The intensity of sunlight at the solar surface in $W \ m^{-2}$ is: