Start Free Mock LoginAlready registered? Login here

Physics - Heat & Thermo Question with Solution | TestHub

PhysicsHeat & ThermoHeat TransferMedium2 min

PhysicsMediuminteger

A 300 W lamp loses all its energy by emission of radiation from the surface of its filament. If the area of surface of filament is 2.4 cm² and is of emissivity 0.4, estimate its temperature. Given that $σ = 1.36 \times 1 0^{- 12}$ cal cm⁻² s⁻¹ K⁻⁴, $J = 4.2$ J cal⁻¹. Neglect the absorption from the surroundings.

Answer:

2447

Solution:

$P = \frac{300}{4.2} = 71.4$ cal/s = $e σ A T^{4}$ , so $T^{4} = \frac{71.4}{0.4 \times 1.36 \times 1 0 ^{- 12} \times 2.4}$ and $T = 2720$ K = $244 7^{\circ}$ C.

Subject:PhysicsTopic:Heat & ThermoSubtopic:Heat Transfer

⏱ 2m

Doubts & Discussion

Loading discussions...