Blundell Thermal Physics · Problem 14.6

Entropy

Physics — Statistical Mechanics · entropy-universe-various-processes

Problem

Calculate the changes in entropy of the Universe as a result of the following processes: ((a)) A capacitor of capacitance 1 μ1\,\muF is connected to a battery of emf. 100 V at 0∘0^\circC. (NB think carefully about what happens when a capacitor is charged from a battery.) ((b)) The same capacitor, after being charged to 100 V, is discharged through a resistor at 0∘0^\circC. ((c)) One mole of gas at 0∘0^\circC is expanded reversibly and isothermally to twice its initial volume. ((d)) One mole of gas at 0∘0^\circC is expanded reversibly and adiabatically to twice its initial volume. ((e)) The same expansion as in (d) is carried out by opening a valve to an evacuated container of equal volume.

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