A composite rod of uniform cross-section has copper and aluminium sections of the same length L in good thermal contact (Figure 4.33). The ends, which are well lagged, are at 10 0 ∘ C and 0 ∘ C. The t

Question

A composite rod of uniform cross-section has copper and aluminium sections of the same length $L$ in good thermal contact (Figure 4.33). The ends, which are well lagged, are at $10 0^{\circ}$ C and $0^{\circ}$ C. The thermal conductivity of copper is twice that of aluminium. Which graph (A) to (D) in the figure represents the variation of $T$ with $x$ in the steady state?

TestHub · Accepted Answer

The heat current is the same in both parts, so L Δ T ​ ∝ K 1 ​ . The gradient in aluminium is twice that in copper. The two straight segments make a drop of 33.3 ∘ C across copper and 66.7 ∘ C across aluminium. That is graph (D), a gentler line followed by a steeper one. D.

Physics - Heat & Thermo Question with Solution | TestHub

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