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Physics · PYQ NEET UG 2018
हिन्दीThe power radiated by a black body is \( P \) and it radiates maximum energy at wavelength, \( \lambda_0 \). If the temperature of the black body is now changed so that it radiates maximum energy at wavelength \( \frac{3}{4}\lambda_0 \), the power radiated by it becomes \( nP \). The value of \( n \) is
Correct answer · Option 3
\( \frac{256}{81} \)
Explanation
By Wien's law, \( T \propto \frac{1}{\lambda} \). Stefan's law gives \( P \propto T^4 \propto \frac{1}{\lambda^4} \). Thus \( \frac{P'}{P} = (\frac{\lambda_0}{\lambda'})^4 = (\frac{\lambda_0}{\frac{3}{4}\lambda_0})^4 = (\frac{4}{3})^4 = \frac{256}{81} \).
