Suppose the same amount of heat energy, say, 260 J is transferred by conduction from a heat reservoir at temperature of 400 K to another reservoir, the temperature of which is (a) 100 K, (b) 200 K, (c) 300 K, and (d) 360 K. We have to calculate the changes in entropy and find the trend.
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Solution: Click For PDF Version
Temperature
at the hot reservoir
Let the
temperature of the cold reservoir to which heat is transferred by
conduction from the hot reservoir be
The amount of
heat transferred by conduction from the hot reservoir to the cold
reservoir
Therefore, the change in entropy of the two reservoirs will be
We next
compute
We find
We note that the change in entropy of the two reservoirs decreases with decrease in difference in their temperatures.
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