Question

A black body at a temperature of 1640 K has the wavelength corresponding to maximum emission equal to 1.75$\mu$. Assuming the moon to be a perfectly black body, the temperature of the moon, if the wavelength corresponding to maximum emission is 14.35 μ is

• A. 100 K
• B. 150 K
• C. 200 K
• D. 250 K

Answer 1

Answer: (C)

200 K

Answer 2

$\frac { T _ { 2 } } { T _ { 1 } } = \frac { \lambda _ { m _ { 1 } } } { \lambda _ { m _ { 2 } } } = \frac { 1.75 } { 14.35 } \Rightarrow T _ { 2 } = \frac { 1.75 } { 14.35 } \times 1640 = 200 \mathrm {~K}$