A bottle holding of water at is placed in a refrigerator whose interior is held at

PHYSICS · Multi-part · Fermi University Physics · Thermal, Statistical & Complex Systems · The laws of thermodynamics · The laws of thermodynamics

Thermal Physics, Ch The second law, entropy and irreversibility

Problem

A bottle holding

1.20\,\mathrm{kg}

of water at

295\,\mathrm{K}

is placed in a refrigerator whose interior is held at

275\,\mathrm{K}

, and is taken out when the water has reached

278\,\mathrm{K}

. Take the specific heat capacity of water as

4180\,\mathrm{J\,kg^{-1}\,K^{-1}}

and constant, neglect the heat capacity of the bottle, and treat the refrigerator interior as a reservoir whose temperature stays at

275\,\mathrm{K}

while it receives the heat from the water. ((a)) Compute the entropy change of the water. ((b)) Compute the entropy change of the refrigerator interior. ((c)) Compute the total entropy change. A student, seeing your answer to (a), objects that the second law forbids an entropy from decreasing, so the sign must be wrong. Say briefly what is wrong with the objection.

Browse the problem library