Thermodynamics Flashcards
Thermodynamics
Is the branch dealing with transformation of heat energy into other forms of energy
Zeroth law of thermodynamics
States that if body A is in equilibrium with body B
And body B is in equilibrium with body C
Then body A is in equilibrium with body C
First law of thermodynamics states that
/\U = /\Q - /\W
It’s based on the law of conservation of energy
Second Law of thermodynamics
(This law gives direction of heat flow)
- Claudia Statement : it’s impossible to construct a machine that transfers heat from low temp. Body to a higher temp. Without any external source
- Kelvin statement : Its impossible to obtain work continuously by cooling an object below the temp. of its surroundings
- Kelvin-Planck Statement : It’s impossible to construct a machine that works on a cyclic process -absorbs heat from source, converts it into work and rejects no heat to the sink. In short it’s impossible to construct a perfect Carnot engine
A perfect Carnot engine can’t be obtained because
It’s impossible to achieve absolute temperature
W=?
P/\V
When V increases W is +ve
When V decrease W is -ve
In case of gases work is done due to
Pressure of gas
Work =
Area of P-V curve
If a cyclic process
Clockwise -> W is +ve
Anti-clockwise -> W is -ve