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Emissive and Absorptive Power

The thermal r...

Question

The thermal radiation emitted by a body is proportional to $T^{n}$ where $T$ is its absolute temperature. The value of $n$ is exactly $4$ for

A

a blackbody

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B

all bodies

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C

bodies painted balck only

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D

polished bodies only

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Solution

The correct option is B all bodies
By Stefan's Law, rate of thermal radiation is directly proportional to fourth power of temperature of the body.
$Q = σ T^{4}$

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