A gold rod and an iron rod are joined end to end in a good thermal contact. The

Question

A gold rod and an iron rod are joined end to end in a good thermal contact. The two rods have equal lengths and radii. The free end of the gold rod is maintained at a temperature of 102 degree C, and the free end of the iron rod is maintained at 0 degree C. Determine the temperature of the interface between the two rods. (Enter your answer to at least the nearest decimal place.) degree C If each rod is 15 cm long and each has a cross-sectional area of 5.2 cm2, what quantity of energy is conducted across the combination in 30 min? kj

Explanation / Answer

Heat flow rate from both rods will be same.

hence Q/t = k_gold A (102 - T) / L = K_iron A (T-0) / L

r and L equal for both rods.

k_gold (102 - T) = k_iron T

k = thermal conductivity of material.

314 ( 102 - T) = 79.5 T

T = 81.4 deg C

(B) Q/t = 314 x (5.2 x 10^-4 ) (102 - 81.4) / 0.15

= 22.4 W

Q = 22.4 x (30 x 60 s) = 40362.9 J

Or 40.35 kJ

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