Question 1: Thermodynamics & KTG

Question

From Wien's displacement law, $\lambda_m T=$ constant $=0.00289 \mathrm{~m}-\mathrm{K}$
Radiation from moon givens $\lambda_m=4700 \mathop A\limits^o$ and another wavelength of $14 	imes 10^{-6} \mathrm{~m}$. Out of the following which conclusion(s) drawn is/are correct with the given information regarding the moon and the sun?
1. Sun radiations are reflected from moon's disc.
2. The temperature of moon's surface is $207 \mathrm{~K}$
3. The temperature of the sun is $6160 \mathrm{~K}$.

Accepted Answer

When $\lambda_m=4700 \mathop A\limits^o=4700 	imes 10^{-10} \mathrm{~m}$
We have the maximum temperature limit as,
$\begin{aligned}
T_{\max } & =\frac{0.00289}{\lambda_m} \
& =\frac{0.00289}{4700 	imes 10^{-10}} \simeq 6160 \mathrm{~K}
\end{aligned}$
And when $\lambda=14 	imes 10^{-6} \mathrm{~m}$
$T_{\min }=\frac{0.00289}{14 	imes 10^{-6}} \simeq 207 \mathrm{~K}$
$207 \mathrm{~K}$ is the temperature of the moon's disc. Since the radiations of sun are reflected from the moon's surface, therefore $6160 \mathrm{~K}$ is the temperature of the sun.

Answer

Only 1

Answer

Both 1 and 2

Answer

Both 2 and 3

Answer

1, 2 and 3

Thermodynamics & KTG

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