At $127^{\circ}C$,the radiated energy is $2.7 \times 10^{-3} \text{ J/s}$. At what temperature in $K$ is the radiated energy $4.32 \times 10^{6} \text{ J/s}$?

$A$ black body of surface area $10 \ cm^2$ is heated to $127^{\circ}C$ and is suspended in a room at temperature $27^{\circ}C$. The initial rate of loss of heat from the body at the room temperature will be ...... $W$.

$A$ black sphere has radius $R$ whose rate of radiation is $E$ at temperature $T$. If the radius is made half and the temperature is made $4T$,the rate of radiation will be: (in $E$)

$A$ very small hole in an electric furnace is used for heating metals. The hole nearly acts as a black body. The area of the hole is $200 \ mm^2$. To keep a metal at $727^{\circ} C$, the heat energy flowing through this hole per second, in joules, is (given $\sigma = 5.67 \times 10^{-8} \ W m^{-2} K^{-4}$):

The value of Stefan's constant is

The temperature at which a black body of unit area loses its energy at the rate of $1 \text{ J/s}$ is: