Question

A black body is at a temperature of $2880K$. The radiation energy emitted by this object with wavelength in between $499$nm and $500$nm is $U_1$, between $999$nm and $1000$nm is $U_2$ and between $1499$nm and $1500$nm is $U_3$. If Wein constant is $2.8\times {10}^6$nmK, 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 $U_2>U_1$

Using Wien's displacement law, we get the wavelength at which intensity is maximum as $1000$ nm. Now, the spectrum of black body radiation looks like as shown in the figure. The energy of radiation corresponds to area under the curve from one wavelength to other. Since the peak is $1000$ nm, we can say that $U_2$ will be greater than both $U_1$ and $U_3$.