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

$A$ particular star (assuming it as a black body) has a surface temperature of about $5 \times 10^4 \ K$. The wavelength in nanometers at which its radiation becomes maximum is $(b = 0.0029 \ mK)$.

The wavelength corresponding to the maximum energy emitted by a body at a certain temperature is ${\lambda _0}$. If the temperature of the body is increased such that the new maximum wavelength becomes $\frac{3{\lambda _0}}{4}$, then by what factor does the emissive power increase?

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

According to Wien's displacement law:

Ordinary bodies $A$ and $B$ radiate maximum energy at wavelengths differing by $4 \mu m$. The absolute temperature of body $A$ is $3$ times that of body $B$. The wavelength at which body $B$ radiates maximum energy is: (in $\mu m$)