Thermodynamic System and Surroundings:
System: A system is a matter or region on which analysis is done.
Surrounding: Everything external to the system where either energy nor mass transaction takes place is known as surrounding.
Boundary: It separate both system and surroundings. it can be fixed or movable.
Fixed Boundary: e.g.rigid box containing gas
Movable boundary: e.g. Cylinder with piston.
Types of system:
|
Types of system
|
Mass transfer
|
Energy transfer
|
Example
|
|
Closed system
|
No
|
Yes
|
Piston cylinder without valves
|
|
Open system
|
Yes
|
Yes
|
Turbine, pump, compressor.
|
|
Isolated
|
No
|
No
|
Universe, Hot coffee in a perfectly isolated
thermos
|
Process:
A thermodynamic process is a change from one equilibrium state to another.
process can be classified into Reversible and Irreversible processes
Reversible process: A process is said to be reversible when reversed in direction it follows the same path as earlier.
Irreversible process: A process is Irreversible because when reversed in direction it doesn't follows the same path.
Cycle:
A cycle is a series of processes forming a closed path whose initial and final points are same.
Similarly a cycle is classified of Reversible and Irreversible cycle.
Reversible cycle: If every process of a cycle is a reversible then the system undergoes a reversible cycle.
Irreversible cycle: Even if a single process is irreversible then the system runs on a irreversible cycle.
Remember: A process can have 100% efficiency but in a cycle 100% efficiency is not possible .
for example water in a Pot can become cool without any external force applied. but for a refrigerator
as it undergoes a cycle an external force(electricity) is applied for cooling.
No comments:
Post a Comment