Question

If wavelength of maximum intensity of radiation emitted by Sun and Moon are $0.5 \times 10^{-6} m$ and $10^{-4}\, m$ respectively, then the ratio of their temperature is

• A. $\frac{1}{10}$
• B. $\frac{1}{50}$
• C. $100$
• D. $200$

Answer 1

Answer: (D)

$\lambda_{m} T_{1}=$ Constant
[Wien's law]
$\Rightarrow \lambda_{1} T_{1}=\lambda_{2} T_{2}$
$0.5 \times 10^{-6} \times T_{1}=10^{-4} \times T_{2}$
$\frac{T_{1}}{T_{2}}=200$