The colour of a shining bright star is an indication of its

The black discs $x, y$ and $z$ have radii $1 \ m, 2 \ m$ and $3 \ m$ respectively. The wavelengths corresponding to maximum intensity are $200 \ nm, 300 \ nm$ and $400 \ nm$ respectively. The relation between emissive power $E_{x}, E_{y}$ and $E_{z}$ is

If the temperature of the sun becomes twice its present temperature,then

Two bodies $A$ and $B$ of equal surface area have thermal emissivities of $0.01$ and $0.81$ respectively. The two bodies are radiating energy at the same rate. Maximum energy is radiated from the two bodies $A$ and $B$ at wavelengths $\lambda_A$ and $\lambda_B$ respectively. The difference in these two wavelengths is $1 \mu m$. If the temperature of body $A$ is $5802 \ K$,then the value of $\lambda_B$ is:

The law used in the measurement of the temperature of stars is .........

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 $\mu m$)