If a black wire of platinum is heated, its colour first appears red, then yellow, and finally white. This can be understood on the basis of:

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

Ordinary bodies $P$ and $Q$ radiate maximum energy with a wavelength difference of $3 \mu m$. The absolute temperature of body $P$ is four times that of $Q$. The wavelength at which body $Q$ radiates maximum energy is (in $\mu m$)

$A$ black body emits radiations of maximum intensity at a wavelength of $5000 \mathring A$,when the temperature of the body is $1227^{\circ}C$. If the temperature of the body is increased by $1000^{\circ}C$,the maximum intensity of emitted radiation would be observed at..... $\mathring A$.

$A$ black disc has a radius $R$ and the wavelength corresponding to the maximum intensity is $\lambda$. The emissive power $(E)$ for the different radii and maximum wavelengths is directly proportional to:

The radiation energy density per unit wavelength at temperature $T$ is maximum at a wavelength $\lambda_0$. At temperature $2T$,it will have a maximum at a wavelength