Consider a one-dimensional rod, 0 ≤ x ≤ L. Assume that the heat energy flowing out of the...

Consider a one-dimensional rod, 0 ≤ x ≤ L. Assume that the heat energy flowing out of the rod at x = L is proportional to the temperature difference between the end temperature of the bar and the known external temperature. Derive (1.3.5); briefly, physically explain why H > 0;