Problem 3P

Below Figure shows graphs of entropy vs. energy for two objects, A and B. Both graphs are on the same scale. The energies of these two objects initially have the values indicated; the objects are then brought into thermal contact with each other. Explain what happens subsequently and why, without using the word “temperature.”

Figure: Graphs of entropy vs. energy for two objects.

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ANSWER:

Step 1:

We know the very fundamental definition of entropy, which is,

----------------------(1)

The inverse of temperature is the rate of change of entropy w.r.t internal energy.

This is true when there is no work done on or by the system.