Question

An adiabatic process is one in which:

• A. External heat enters in the system
• B. External heat leave in the system
• C. No external heat enters or leaves the system
• D. Heat transmission depend upon the ambient temperature

Hint:

Remember the key conditions for thermodynamic processes:
- Adiabatic: $dQ = 0$
- Isothermal: $dT = 0$
- Isobaric: $dP = 0$
- Isochoric: $dV = 0$

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
In thermodynamics, processes are classified based on how state variables like pressure, volume, temperature, and heat change.
An adiabatic process is one where there is no exchange of heat between the system and its surroundings.
Key Formula or Approach:
The First Law of Thermodynamics is expressed as: \[ dU = dQ - dW \] Where: - $dU$ is the change in internal energy.
- $dQ$ is the heat exchange.
- $dW$ is the work done.

Step 2: Detailed Explanation:
In an adiabatic process, the system is thermally insulated from its environment, meaning no heat energy is transferred across its boundary.
This is mathematically written as: \[ dQ = 0 \] Substituting this into the First Law gives: \[ dU = -dW \] This indicates that: - If the system expands adiabatically (work is done by the system, $dW > 0$), its internal energy decreases ($dU < 0$), causing the temperature to drop.
- If the system is compressed adiabatically (work is done on the system, $dW < 0$), its internal energy increases ($dU > 0$), causing the temperature to rise.
These processes typically occur in thermally insulated systems or happen too quickly for heat exchange to take place (such as the compression stroke in an internal combustion engine).
Thus, Option (C) matches the definition of an adiabatic process.

Step 3: Final Answer:
The correct option is (C).