According to Wien's displacement law:

The wavelength of radiation emitted by a body depends upon

On observing light from three different stars $P, Q$ and $R$, it was found that the intensity of violet colour is maximum in the spectrum of $P$, the intensity of green colour is maximum in the spectrum of $R$, and the intensity of red colour is maximum in the spectrum of $Q$. If $T_P, T_Q$ and $T_R$ are the respective absolute temperatures of $P, Q$ and $R$, then it can be concluded from the above observations that:

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 $\,kcal$)

If the wavelengths of maximum intensity of radiation emitted by two black bodies $A$ and $B$ are $0.5 \mu m$ and $0.1 \ mm$ respectively,then the ratio of the temperatures of the bodies $A$ and $B$ is

The wavelength of maximum emission of radiation from a body at $2000 \ K$ is $4 \ \mu m$. What is the wavelength of maximum emission of radiation from the body at $2400 \ K$ in $\mu m$?