Question

A black body has maximum wavelength ${\lambda }_m$ at $2000K$. Its corresponding wavelength at $3000K$ is:

• A. $\frac{16}{81}{\lambda }_m$
• B. $\frac{3}{2}{\lambda }_m$
• C. $\frac{81}{16}{\lambda }_m$
• D. $\frac{2}{3}{\lambda }_m$

Answer 1

Answer: (D)

$\frac{2}{3}{\lambda }_m$

Applying Wein's displacement law.
$\lambda T=$constant
${\lambda }_{1m}{T}_1={\lambda }_{2m}{T}_2$
${\lambda }_m\times 2000=\lambda \times 3000$
$\lambda =\frac{2}{3}{\lambda }_m$