$A$ container has a small hole. At what temperature (in $K$) should it be maintained so that it emits $1 \ cal$ of energy per second per $m^2$?

If the temperature of a black body increases from $7^{\circ}C$ to $287^{\circ}C$,then what is the ratio of the rate of energy emission?

The temperatures of two bodies $A$ and $B$ are $727^{\circ}C$ and $127^{\circ}C$. The ratio of the rate of emission of radiations will be:

$A$ black rectangular surface of area '$A$' emits energy '$E$' per second at $27^{\circ} C$. If length and breadth are reduced to $\frac{1}{3}$ of their initial values and the temperature is raised to $327^{\circ} C$,then the energy emitted per second becomes:

Two spheres of the same material have radii $r_1$ and $r_2$ and surface temperatures $T_1$ and $T_2$ respectively. If their emissive power (total power radiated) is the same,find the ratio of their radii $r_1/r_2$.

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