The two ends of a uniform lagged rod of thermal conductivity k are maintained at different but constant temperatures. The temperature gradient at any point on the rod is d ℓ d θ (equal to the differ

Question

The two ends of a uniform lagged rod of thermal conductivity k are maintained at different but constant temperatures. The temperature gradient at any point on the rod is d ℓ d θ ​ (equal to the difference in temperature per unit length). The heat flow per unit time per unit cross-section of the rod is I .

TestHub · Accepted Answer

Steady state in a lagged uniform rod: the heat current $I$ is the same at every section, so (B) false.

The stem defines the gradient as the difference in temperature per unit length, i.e. the positive temperature drop per unit length along the rod.

$I = k \frac{d θ}{d ℓ}$

With $k$ and $I$ constant, the gradient is the same at all points. (A) true, (C) true. (D) false.

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