Question

Which of the following rods, (given radius r and length l) each made of the same material and whose ends are maintained at the same temperature will conduct most heat?

(a) r = r₀, l = l₀

(b) r = 2r₀, l = l₀

(c) r = r₀, l = 2l₀

(d) r = 2r₀, l = 2l₀

Answer 1

Correct option (b) r = 2r₀, l = l₀

Explanation:

Heat conducted

The rod with the maximum ratio of A/l will conduct most. Here the rod with r = 2r₀ and l = l₀ will conduct most.