Question

A black body is at rest at a temperature of $2880\text{K}$. The energy of radiation emitted by this object with wavelength between $499\text{n-m}$ and $500\text{n-m}$ is $U_1$, between $999$ and $1000\text{nm}$ is $U_2$ and between $1499\text{nm}$ and $1500\text{nm}$ is $U_3$. The Wien's constant $b=2.88\times {10}^6\text{nm-K}$. Then

• A. $U_1=0$
• B. $U_3=0$
• C. $U_1>U_2$
• D. $U_2>U_1$

Answer 1

The correct option is D $U_2>U_1$

Given, Temperature of black body $\left(T\right)=2880\text{K}$
From Wien's law
${\lambda }_{max}=\frac{2.88\times {10}^6}{2880}=1000\text{nm}$


Energy distribution with wavelength is as shown in the figure.
From the figure it is clear that $U_2$ is corresponding to ${\lambda }_{max}$(approx)
$\therefore U_2>U_1$