Two pots are identical except that the flat bottom of one is aluminum, whereas that of the other is copper. Water in these pots is boiling away at 100.0 ˚C at the same rate. The temperature of the heating element on which the aluminum bottom is sitting is 161 ˚C. Assume that heat enters the water only through the bottoms of the pots and find the temperature of the heating element on which the copper bottom rests.

Rate of flow of heat = K X (t₂ - t₁) xA/L

K is thermal conductivity, t₂ - t₁ = temperature difference, A is area of surface and L is thickness of separating medium

In the given case only K and t₂ are different, otherwise all others are equal.

So

Since rate of heat flow are equal

K₁ X (t-100) = K₂ X (161 - 100)

t is temperature of source of heat near copper bottom.

K₁ and K₂ are thermal conductivity of copper and aluminium.

K₁ / K₂ = 61 / (t - 100)

385/205 = 61/t - 100

385t - 38500 = 12505

385t = 51005

t = 133.77 C.