Definition & Explanation of Isobaric and Isochoric
In thermodynamics, isobaric and isochoric processes describe how gases behave under different conditions. An isobaric process happens at constant pressure, where the volume changes as heat is added or removed. An isochoric process occurs at constant volume, meaning pressure changes instead of volume. These processes are important in engines, refrigerators, and heat transfer systems. Understanding their differences helps in learning how energy moves in gases and real-world applications like combustion engines and heat exchangers.
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FAQs on Difference Between Isobaric and Isochoric Thermodynamic Process
1. What is the difference between isobaric and isochoric specific heat?
In an isobaric process, heat capacity is denoted by Cp (specific heat at constant pressure), and in an isochoric process, it is Cv (specific heat at constant volume). Cp is always greater than Cv because at constant pressure, the system also does work.
2. What is an example of an isochoric process in thermodynamics?
A simple example of an isochoric process is heating gas inside a sealed rigid container. Since the container’s volume doesn’t change, the pressure increases with temperature.
3. What is an example of an isobaric process?
An example of an isobaric process is boiling water in an open pot. The atmospheric pressure remains constant while heat increases the temperature and volume of water vapor.
4. What is the difference between a thermodynamic system and a thermodynamic process?
Thermodynamic System: A defined quantity of matter where energy interactions occur.
Thermodynamic Process: A change in the state of a thermodynamic system due to heat or work transfer.
5. What are the four thermodynamic processes?
The four basic thermodynamic processes are:
Isothermal – Constant temperature
Adiabatic – No heat transfer
Isobaric – Constant pressure
Isochoric – Constant volume
6. What is the zeroth law of thermodynamics?
The Zeroth Law of Thermodynamics states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This law defines the concept of temperature.
7. What is the PV diagram for the isobaric and isochoric processes?
The PV (Pressure-Volume) diagram represents how pressure and volume change during a thermodynamic process:
Isobaric Process: Appears as a horizontal line because pressure remains constant while volume changes.
Isochoric Process: Appears as a vertical line because volume remains constant while pressure changes.
8. Which thermodynamic process is fast?
The Adiabatic process is the fastest because it occurs without heat transfer (Q = 0), meaning all energy changes happen instantly due to pressure and volume changes. This is seen in explosions or rapid compression of gases in an engine.
9. What do you mean by entropy?
Entropy is a measure of disorder or randomness in a system. It indicates how energy is spread or lost in a process. According to the Second Law of Thermodynamics, entropy always increases in a natural process, meaning systems tend to move toward disorder.
Example: Ice melting into water increases entropy because molecules become more disordered.
10. What are the 3 types of thermodynamic systems?
Open System – Exchanges both mass and energy with surroundings. (e.g., boiling water in an open pot).
Closed System – Exchanges only energy but not mass. (e.g., a closed water bottle being heated.)
Isolated System – No exchange of mass or energy. (e.g., a thermos flask.)
