Question

The number of degrees of freedom required for description of pure gas are

• A. 1
• B. 2
• C. 0
• D. 3

Hint:

To describe a pure gas, three parameters — pressure, volume, and temperature — are required, giving the system three degrees of freedom.

Answer 1

The Correct Option is D

Step 1: Understanding degrees of freedom.
Degrees of freedom refer to the number of independent parameters that are needed to define the state of a system. For a pure gas, we need three parameters: pressure, volume, and temperature, which are the typical thermodynamic variables used to describe a pure gas.
Step 2: Analyzing the options.
(1) 1: This is incorrect as we need more than 1 parameter to define the state of a gas.
(2) 2: This is also incorrect as we need more than 2 parameters.
(3) 0: This is incorrect. The system requires at least 1 parameter to be defined.
(4) 3: Correct — The three degrees of freedom correspond to the three parameters needed to define the state of a pure gas (pressure, volume, temperature).
Step 3: Conclusion.
The correct number of degrees of freedom for describing a pure gas is (4) 3.