At $273^{\circ} C$,the emissive power of a perfectly black body is $R$. Its emissive power at $0^{\circ} C$ is:

If $A$ represents Boltzmann constant,$B$ represents Planck's constant and $C$ represents speed of light in vacuum,then the quantity having the dimensions of $A^4 B^{-3} C^{-2}$ is

The $SI$ unit and dimension of Stefan's constant $\sigma$ in the case of Stefan's law of radiation are

Two spheres $S_{1}$ and $S_{2}$ have radii $R$ and $3R$ and temperatures $T$ and $T/3$ respectively. If they are coated with a material of the same emissivity, and the rate of radiation of $S_{1}$ is $E$, then the rate of radiation of $S_{2}$ is:

The rate of radiation by a black body is $R$ at temperature $T$. Another body has the same area but an emissivity of $0.2$ and a temperature of $3T$. Its rate of radiation is: (in $R$)

The ratio of energies of radiation emitted by a black body at $600 \ K$ and $900 \ K$ when the surrounding temperature is $300 \ K$ is: (in $/16$)