$A$ black body radiates at the rate of $W$ watts at a temperature $T$. If the temperature of the body is reduced to $T/3$,it will radiate at the rate of (in Watts):

The temperature of a spherical black body is inversely proportional to its radius. If its radius is doubled,then the power radiating from it will be

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

For two identical cylindrical emitters,the ratio of their radii is $1:4$ and the ratio of their temperatures is $2:1$. The ratio of the amount of heat emitted by them is ....... (Assume length is proportional to radius for the cylinders).

The wavelength of maximum intensity of radiation emitted by a star is $289.8 \ nm$. The radiation intensity of the star is (Stefan's constant $= 5.67 \times 10^{-8} \ W m^{-2} K^{-4}$,Wien's constant $b = 2898 \ \mu m \ K$).

$A$ black body at a temperature of $127^{\circ}C$ radiates heat at the rate of $1 \ cal/cm^2 \cdot s$. At a temperature of $527^{\circ}C$,the rate of heat radiation from the body in $cal/cm^2 \cdot s$ will be: