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Thermodynamics - Lecture - 4

 Laws of thermodynamics

Zeroth law of thermodynamics

First law of thermodynamics

Second law of thermodynamics

Third law of thermodynamics


Zeroth law of thermodynamics

If two systems are in thermal equilibrium with a third system, they must be in thermal equilibrium with each other.

or

In other words

If a body C, be in thermal equilibrium with two other bodies, A and B, then A and B are in thermal equilibrium with one another.


First law of thermodynamics

Known as the law of conservation of energy.

This states that energy can be neither created nor destroyed. However, energy can change forms, and energy can flow from one place to another.

* The total energy of an isolated system does not change.

The increase in internal energy of a closed system is equal to the heat supplied to the system minus work done by it.
dUsystem=Q - W

We can say
Qsystem= W + dU

Qsystem= W

100% Efficiency




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