Q. Temperatures of two stars are in ratio 3:2. If wavelength of maximum intensity of first body is 4000$\mathring{\mathrm{A}}$, what is corresponding wavelength second body?
A) 9000$\mathring{\mathrm{A}}$
B) 6000$\mathring{\mathrm{A}}$
C) 2000$\mathring{\mathrm{A}}$
D) 8000$\mathring{\mathrm{A}}$
Explanation
(b) According to Wien’s displacement law
$\lambda_{m}T = constant$
$\therefore\ \ \ \ \ \ \ \ \ \frac{\left( \lambda_{m} \right)_{1}}{\left( \lambda_{m} \right)_{2}} = \frac{T_{2}}{T_{1}}$
Here $\frac{T_{1}}{T_{2}} = \frac{3}{2},\ \left( \lambda_{m} \right)_{1} = 4000\mathring{\mathrm{A}} = 4000 \times 10^{- 10}$m
$\therefore\ \ \ \ \ \ \left( \lambda_{m} \right)_{2} = \frac{4000 \times 10^{- 10} \times 3}{2} = 6000\mathring{\mathrm{A}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.