The wavelength of the radiation emitted by a black body is $6 \ mm$ and Wien's constant is $3 \times 10^{-3} \ mK$. Then the temperature of the black body is (in $K$)

Which of the following is the $\nu_m - T$ graph for a perfectly black body? ($\nu_m$ = maximum frequency of radiation,$T$ = absolute temperature)

$A$ black body radiates maximum energy at wavelength $\lambda$ and its emissive power is $E$. Now,due to a change in the temperature of that body,it radiates maximum energy at wavelength $\frac{2 \lambda}{3}$. At that temperature,the emissive power is:

The absolute temperatures of two black bodies are $2000 \ K$ and $3000 \ K$ respectively. The ratio of wavelengths corresponding to maximum emission of radiation by them will be

State and explain Wien's displacement law.

Solar radiation emitted by the sun resembles that emitted by a black body at a temperature of $6000 \ K$. Maximum intensity is emitted at a wavelength of about $4800 \ \mathring{A}$. If the sun were to cool down from $6000 \ K$ to $3000 \ K$,then the peak intensity would occur at a wavelength of ....... $\mathring{A}$.