The minimum temperature of a body at which it emits visible light is approximately.......$^oC$.

Three stars $A, B, C$ have surface temperatures $T_{A}, T_{B}, T_{C}$ respectively. Star $A$ appears bluish,star $B$ appears reddish,and star $C$ appears yellowish. Hence,

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

The wavelength of maximum intensity of radiation emitted by a star is $289.8 \, nm$. The radiation intensity of the star is (Stefan's constant $\sigma = 5.67 \times 10^{-8} \, W m^{-2} K^{-4}$, Wien's constant $b = 2898 \, \mu m K$).

Black bodies $A$ and $B$ radiate maximum energy with wavelength difference $4 \mu m$. The absolute temperature of body $A$ is $3$ times that of $B$. The wavelength at which body $B$ radiates maximum energy is (in $\mu m$)

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