Two plates A and B have thermal conductivities 84\ W\,m^-1K^-1 and 126\ W\,m^-1K^-1 respectively. They have same surface area and same thickness. They are placed in contact along their surfaces. If t…

Question

Two plates A and B have thermal conductivities 84\ W\,m^-1K^-1 and 126\ W\,m^-1K^-1 respectively. They have same surface area and same thickness. They are placed in contact along their surfaces. If the temperatures of the outer surfaces of A and B are kept at 100° C and 0°C respectively, then the temperature of the surface of contact in steady state is_____°C.

Accepted Answer

Correct answer: 40. (40) Let the temperature of the contact surface be T, So, H_A = H_B K_AA '(T_A-T)L= K_BA '(T-T_B)L ⇒84(100-T)=126(T-0) ⇒2(100-T)=3T ⇒T=40^0C

Solution

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