For a black body at temperature $727^{\circ} C$,its radiating power is $60\; W$ and the temperature of the surrounding is $227^{\circ} C$. If the temperature of the black body is changed to $1227^{\circ} C$,then its radiating power will be ..... $W$.

The total radiant energy per unit area,normal to the direction of incidence,received at a distance $R$ from the centre of a star of radius $r$,whose outer surface radiates as a black body at a temperature $T \ K$ is given by

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 $R$)

$A$ thin square steel plate with each side equal to $10$ cm is heated by a blacksmith. The rate of radiated energy by the heated plate is $1134$ $W$. The temperature of the hot steel plate is ....... $K$ (Stefan's constant $\sigma = 5.67 \times 10^{-8} \text{ W m}^{-2} \text{ K}^{-4}$,emissivity of the plate = $1$).

Obtain the equation for the rate of emission of heat for a perfect black body by using the Stefan-Boltzmann law.

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 ....... $K$.