Start Free Mock LoginAlready registered? Login here

Physics - Heat & Thermo Question with Solution | TestHub

PhysicsHeat & ThermoHeat TransferHard2 min

PhysicsHardnumerical

A solid aluminium sphere (density 2700 kg m⁻³, specific heat 900 J kg⁻¹ K⁻¹) of radius 5 cm is at 300 K in a chamber whose walls are near 0 K. Treat it as a black body. Find the time for it to cool to 150 K, in hours.

Answer:

17.10

Solution:

$t = \frac{r ρ c}{9 σ} (\frac{1}{T _{2}^{3}} - \frac{1}{T _{1}^{3}}) = \frac{0.05 \times 2700 \times 900}{9 \times 5.67 \times 1 0 ^{- 8}} (\frac{1}{15 0 ^{3}} - \frac{1}{30 0 ^{3}}) = 6.173 \times 1 0^{4}$ s = $17.1$ h.

Subject:PhysicsTopic:Heat & ThermoSubtopic:Heat Transfer

⏱ 2m

Doubts & Discussion

Loading discussions...