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Physics - Heat & Thermo Question with Solution | TestHub

PhysicsHeat & ThermoHeat TransferMedium2 min

PhysicsMediumnumerical

A cube $a = 3.0$ cm on each side radiates energy at the rate of $P = 20$ J/s when its temperature is 727°C and surrounding temperature 27°C. Determine its emissivity.

Answer:

0.07

Solution:

$A = 6 a^{2} = 5.4 \times 1 0^{- 3}$ m². $e = \frac{P}{σ A ( T ^{4} - T _{0}^{4} )} = \frac{20}{5.67 \times 1 0 ^{- 8} \times 5.4 \times 1 0 ^{- 3} \times ( 100 0 ^{4} - 30 0 ^{4} )} = 0.066$ .

Subject:PhysicsTopic:Heat & ThermoSubtopic:Heat Transfer

⏱ 2m

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