Question

The intensity of radiation emitted by the sun has its maximum value at a wavelength of $510$ nm and that emitted by the North star has the maximum value at $350$ nm. If these stars behave like black bodies, then the ratio of the surface temperatures of the sun and the north star is:

• A. 1.46
• B. 0.69
• C. 1.21
• D. 0.83

Answer 1

The correct option is B 0.69

Using Wien,s displacement law, ${\lambda }_{m}T=$ constant, we get here

$\frac{T_S}{T_N}=\frac{{\lambda }_m\left(N\right)}{{\lambda }_m\left(S\right)}=\frac{350}{510}=0.69$