Physics 4-Thermodynamics

Front 1

Second law two statements

Back 1

Kelvin plank statement: impossible to convert heat completely into work.

Clausius statement: Cannot transfer heat from a cold body to hot body without expending work.

Front 2

Equivalence of kelvin plank and clausius statement

Back 2

1. Assume clausius and combine refrigerator and heat engine.

2. Assume kelvin plank and combine refrigerator and heat engine.

Remember refrigerator takes heat from cold to hot

Front 3

Area of T-S diagram gives

Back 3

Quantity of heat

Front 4

Clausius theorem + proof

Back 4

In any reversible cycle the net change in entropy is zero.

Assume zero entropy change for Carnot cycle.

Divide cycle into small Carnot cycles.

Sum each Carnot cycle

Front 5

Prove entropy is a state function.

Back 5

Draw cycle reversible.

Net Change in entropy of cycle zero.

Change direction in return path.

Hence prove that entropy is path independent or it's a state function.

Front 6

Entropy of an isolated system

Back 6

Always increases as the entropy of the universe is the same as entropy of the system.