Two concentric metallic shells of negligible thickness have radii 4 cm and 12 cm. The space between them holds a medium of conductivity 2 W m⁻¹ K⁻¹. The inner shell is at 80°C and the outer shell at 2

Question

Two concentric metallic shells of negligible thickness have radii 4 cm and 12 cm. The space between them holds a medium of conductivity 2 W m⁻¹ K⁻¹. The inner shell is at 80°C and the outer shell at 20°C. Find the heat current from inner to outer shell, in W.

Answer:

90.50

Solution:

$P = \frac{4 πk r _{1} r _{2} Δ T}{r _{2} - r _{1}} = \frac{4 π \times 2 \times 0.04 \times 0.12 \times 60}{0.08} = 90.5$ W.

TestHub · Accepted Answer

P = r 2 ​ − r 1 ​ 4 πk r 1 ​ r 2 ​ Δ T ​ = 0.08 4 π × 2 × 0.04 × 0.12 × 60 ​ = 90.5 W.

Physics - Heat & Thermo Question with Solution | TestHub

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