Question

A black body at $1373$ $?$ emits maximum energy corresponding to a wavelength of $1.78$ microns. The temperature of the moon for which $\lambda _{m}=14$ micron would be

• A. $62.6?$
• B. $-58.9?$
• C. $-63.7?$
• D. $64.2?$

Answer 1

Answer: (C)

$-63.7?$

Answer 2

$\frac{T_{2}}{T_{1}}= \, \frac{\lambda _{m_{1}}}{\lambda _{m_{2}}}=\frac{1.78}{14}$ $T_{2}=\frac{1.78}{14} \, \times T_{1}=\frac{1.78}{14}\left(1373 + 273\right)$ $=209.3K=209.3$ $-273=-63.7?$