The emissive power of a sphere of area $0.04 \,m^2$ is $0.7 \,kcal \,s^{-1} \,m^{-2}$. The amount of heat radiated in $20 \,s$ is: (in $\,kcal$)

The following graph represents the radiant power versus wavelength of a black body. The area under the curve represents:

$A$ perfect black body has a maximum wavelength $\lambda_m$ at a temperature of $2000 \, K$. What will be its maximum wavelength at a temperature of $3000 \, K$?

The distribution of relative intensity $I(\lambda)$ of blackbody radiation from a solid object versus the wavelength $\lambda$ is shown in the figure. If the Wien displacement law constant is $2.9 \times 10^{-3} \ mK$,what is the approximate temperature of the object in $K$?

Ordinary bodies $A$ and $B$ radiate maximum energy at wavelengths differing by $4 \mu m$. The absolute temperature of body $A$ is $3$ times that of body $B$. The wavelength at which body $B$ radiates maximum energy is: (in $\mu m$)

If the wavelengths of maximum intensity of radiations emitted by the sun and the moon are $0.5 \times 10^{-6} \ m$ and $10^{-4} \ m$ respectively,the ratio of their temperatures is: