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MHT CET 2026 (15 Apr, Shift 2) · Thermal Radiation: Black Body, Stefan & Wien

Thermal Radiation: Black Body, Stefan & Wien question from MHT CET 2026 (15 Apr, Shift 2)

Q29MHT CET 2026 · 15 APR · SHIFT 2Medium

Thermal Radiation: Black Body, Stefan & Wien

A black rectangular surface of area A emits energy E per second at $127^\circ$ C. If length and breadth is reduced to half of initial value and temperature is raised to $527^\circ$ C then energy emitted becomes

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Answer: (c)

$E \propto A T^4$ .
Length and breadth halved: $A \to \frac{A}{4}$ .
$T: 400\text{ K} \to 800\text{ K}$ , factor $16$ .
$E' = \frac{16}{4}E = 4E$ , so the answer is (c).

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