Question

A black body emits maximum energy at wavelength $\lambda_0$ when temperature is $T_1$. At temperature $T_2$, it emits maximum energy at $\frac{4}{5} \lambda_0$? Ratio of the two temperature $T_1: T_2$ is

• A. 1:01
• B. 4:05
• C. 5:04
• D. 16:25

Answer 1

Answer: (B)

4:05

Answer 2

According to Wein's displacement law
$\lambda T$ = constant or, $\lambda_1 T_1 = \lambda_2 T_2$
Here, at temperature $T_1, \lambda_1 = \lambda_0$ at temperature $T_2 , \lambda_2 = \frac{4}{5} \lambda_0$
$\therefore \, \, \, \lambda_0T_1 = \frac{4}{5} \lambda_0 T_2$ or $\frac{T_1}{T_2} = \frac{4}{5}$