In determining the temperature of a distant star,one makes use of

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

Four pieces of iron heated in a furnace to different temperatures show different colours listed below. Which one has the highest temperature?

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

The following graph represents the radiant power versus wavelength of a black body. The area under the curve represents:

The wavelength of maximum emitted energy $(\lambda_m)$ of a body at $700 \ K$ is $4.08 \ \mu m$. If the temperature of the body is raised to $1400 \ K$,then the value of $\lambda_m$ will be (in $\mu m$)