1. What is thermodynamics?
Thermodynamics is the study of heat, energy, and their transformations.
It explains how energy flows between systems and how it affects work and temperature.
2. Explain the laws of thermodynamics ?
Zeroth law defines temperature equality, first law is energy conservation, second law explains entropy, and third law states entropy becomes zero at absolute zero. Together, they describe how energy behaves in all systems.
3. What is the difference between heat and work?
Heat is energy transfer due to temperature difference, while work is energy transfer due to force or motion. Both are boundary phenomena and not stored in a system.
4. Define system, surroundings, and boundary ?
| Term | Definition | Key Points |
|---|---|---|
| System | The part of the universe selected for study. | Can be open, closed, or isolated depending on mass/energy exchange. |
| Surroundings | Everything outside the system that can interact with it. | Interacts with the system through heat, work, or mass (in open systems). |
| Boundary | The real or imaginary surface that separates the system from surroundings. | Can be fixed or movable; determines what enters or leaves the system. |
5. What is entropy?
Entropy is a measure of disorder or randomness. Higher entropy means more energy is unavailable for useful work.
6. What is the Zeroth Law of Thermodynamics?
If two bodies are each in thermal equilibrium with a third body, they are in thermal equilibrium with each other. It forms the basis of temperature measurement.
7. Explain enthalpy ?
Enthalpy is the total heat content of a system. It is useful for studying heat changes at constant pressure.
8. What is a thermodynamic process?
A thermodynamic process is any change in the state of a system. Examples include isothermal, adiabatic, isobaric, and isochoric processes.
9. Difference between open, closed, and isolated systems.
| Type of System | Definition | Mass Transfer | Energy Transfer (Heat/Work) | Example |
|---|---|---|---|---|
| Open System | A system that exchanges both mass and energy with its surroundings. | Yes | Yes | Boiler, human body, turbine |
| Closed System | A system that exchanges only energy but not mass with surroundings. | No | Yes | Piston–cylinder with fixed mass |
| Isolated System | A system that exchanges neither mass nor energy with surroundings. | No | No | Thermos flask (ideal), universe |
10. What is steady-state and unsteady-state?
In steady-state, properties remain constant with time. In unsteady-state, properties change with time.