Dear Student,
Please find below the solution to your problem.
Let the thermal resistance of Al cube be R1.
Let the thermal resistance of Cu cube be R2.
Applying the formula of thermal resistance,
R = l/KA
Thermal resistance of Al will be
R1 = l/KA
R1 = 3 × (10^-2)/209 × (3 × 10^-2)^2
R1 = 0.159 K/W
Calculation of thermal resistance of Cu
R2 = l/KA
R2 = 3 × (10^-2)/385 × (3 × 10^-2)^2
R2 = 0.086 K/W
From the figure we can clearly see that the given two resistances are connected in parallel way, so their equivalent resistance will be -
R = (R1R2/R1 + R2)
R = 0.159 × 0.086/(0.159 + 0.086)
R = 0.055 K/W
the total thermal current from one reservior to the other = Thermal Difference/Thermal Resistance
= (100 – 20)/0.055
= 1.45 × 10^3 W
Hence, the required answer is 1.45 × 10^3
Thanks and Regards