Question

In an adiabatic process:

• A. Heat transfer occurs
• B. No heat transfer occurs
• C. Temperature is constant
• D. Pressure is constant

Hint:

An adiabatic boundary is equivalent to a perfectly insulated wall.
Remember:
Adiabatic $\rightarrow Q = 0$
Isothermal $\rightarrow \Delta T = 0$
Isobaric $\rightarrow \Delta P = 0$

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the defining characteristic of an adiabatic process.
Thermodynamic processes are classified based on which state variable or energy interaction is held constant during the transition.

Step 2: Key Formula or Approach:
The first law of thermodynamics is written as:
\[ dU = dQ - dW \]
where:
$dU$ is the change in internal energy.
$dQ$ is the heat exchange.
$dW$ is the work done by the system.

Step 3: Detailed Explanation:

• An adiabatic process is defined as a thermodynamic process in which there is no transfer of heat or mass between the thermodynamic system and its surroundings.

• Mathematically, this is expressed as:
\[ dQ = 0 \quad (\text{or } Q = 0) \]

• Since no heat enters or leaves the system, any work done by the system is done at the expense of its internal energy ($dU = -dW$), which generally results in a change in temperature.

• Other processes for comparison:
- Isothermal process: Temperature remains constant ($dT = 0$).
- Isobaric process: Pressure remains constant ($dP = 0$).
- Isochoric process: Volume remains constant ($dV = 0$).

Step 4: Final Answer:
Therefore, in an adiabatic process, no heat transfer occurs.