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MHT CET 2025 (26 Apr, Shift 1) · Thermal Radiation: Black Body, Stefan & Wien

Thermal Radiation: Black Body, Stefan & Wien question from MHT CET 2025 (26 Apr, Shift 1)

Q57MHT CET 2025 · 26 APR · SHIFT 1Medium

Thermal Radiation: Black Body, Stefan & Wien

Two black spheres $P \,\&\, Q$ have radii in the ratio $4 : 3$ . The wavelength of maximum intensity of radiation are in the ratio $4 : 5$ respectively. The ratio of radiated power by P to Q is

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Answer: (a)

$P \propto r^2 T^4$ and Wien gives $T \propto \frac{1}{\lambda_m}$ , so $P \propto \frac{r^2}{\lambda_m^4}$ .
$\frac{P_P}{P_Q} = \left(\frac{4}{3}\right)^2 \left(\frac{5}{4}\right)^4 = \frac{16}{9} \times \frac{625}{256}$
$= \frac{625}{144}$ , so the answer is (a).

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