The rate of dissipation of heat by a black body at temperature $T$ is $Q$. What will be the rate of dissipation of heat by another body at temperature $2T$ and emissivity $0.25$ (in $Q$)?

$A$ 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 area of the hole of a heat furnace is $10^{-4} \ m^2$. It radiates $1.58 \times 10^5 \ cal$ of heat per hour. If the emissivity of the furnace is $0.80$,then its temperature is .......... $K$.

If the temperature of a black body increases from $7\,^{\circ}C$ to $287\,^{\circ}C$,then the rate of energy radiation increases by

$A$ black body radiates energy at the rate of $E \ W/m^2$ at a high temperature $T \ K$. When the temperature is reduced to $\frac{T}{2} \ K$,the radiant energy will be

Parallel rays of light of intensity $I = 912 \ W m^{-2}$ are incident on a spherical black body kept in surroundings of temperature $T_0 = 300 \ K$. Take Stefan-Boltzmann constant $\sigma = 5.7 \times 10^{-8} \ W m^{-2} K^{-4}$ and assume that the energy exchange with the surroundings is only through radiation. The final steady state temperature of the black body is close to: (in $K$)