Two stars $A$ and $B$ radiate maximum energy at wavelengths $3.9 \times 10^{-7} \text{ m}$ and $5.2 \times 10^{-7} \text{ m}$ respectively. The ratio of the temperature of star $A$ to that of star $B$ will be

$A$ black body at $1227\,^oC$ emits radiations with maximum intensity at a wavelength of $5000\,\mathring{A}$. If the temperature of the body is increased by $1000\,^oC$,the maximum intensity will be at ....... $\mathring{A}$.

Wien's displacement law expresses the relation between:

Two stars $A$ and $B$ radiate maximum energy at the wavelengths of $360 \ nm$ and $480 \ nm$ respectively. Then the ratio of the surface temperatures of $A$ and $B$ is

On increasing the temperature of a substance gradually, which of the following colours will be noticed by you?

$A$ 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: