A compound rod 1.5 m long has a steel core 2 cm in diameter surrounded by a brass casing of outer diameter 4 cm. Its outer surface is insulated and its ends are held at 100°C and 0°C. k s t ee l = 1

Question

A compound rod 1.5 m long has a steel core 2 cm in diameter surrounded by a brass casing of outer diameter 4 cm. Its outer surface is insulated and its ends are held at 100°C and 0°C. k s t ee l ​ = 12 and k b r a ss ​ = 110 cal m⁻¹ K⁻¹ s⁻¹. Find the heat current in the rod, in cal/s.

TestHub · Accepted Answer

Parallel conduction: A s ​ = π 1 2 = 3.142 cm², A b ​ = π ( 2 2 − 1 2 ) = 9.425 cm². I = 1.5 100 ​ ( 12 × 3.142 + 110 × 9.425 ) × 1 0 − 4 = 7.16 cal/s. (Brass carries 96% of it.)

Physics - Heat & Thermo Question with Solution | TestHub

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