Question

As lab consists of two parallel layers of copper and brass of the same thickness and having thermal conductivities in the ratio 1 : 4. If the free face of brass is at 100ºC and that of copper at 0⁰C, the temperature of interface is –

• A. 80⁰C
• B. 20⁰C
• C. 60⁰C
• D. 40⁰C

Answer 1

Answer: (A)

80⁰C

Answer 2

4K(100 – q) = K (q – 0)

̃ 400 – 4q = q

̃ q = 80ºC