Q 11-10-032NEETJEE MainEAMCET 2012 (Engineering)Medium
The power radiated by a black body is $P$ and it radiates maximum energy around the wavelength $\lambda_0$. If the temperature of the black body is now changed so that it radiates maximum energy around a wavelength $\dfrac{\lambda_0}{2}$, the power radiated becomes
Answer: (B) $16P$
Concept. Wien's law $\lambda_mT = b$ gives the new temperature; Stefan's law $P \propto T^4$ gives the power.
Step 1. Temperature. Halving $\lambda_m$ doubles $T$.
Step 2. Power. $P' = 2^4P = 16P$.
Answer. $16P$ (Option B).
Solution by Sreeraj P, M.Sc Physics