Internal Energy of Monoatomic Gas – Rankers Physics

Kinetic Theory of Gases: Practice Problem & Solution

Assertion (A): In an ideal monoatomic gas, The Internal energy of gas is equal to translational Kinetic energy of all its molecules Reason (R): The Internal energy may get contributes from Translational, Rotatory, vibrationally as well as from the Potential energy corresponding to the molecular force.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Kinetic Theory of Gases. Understanding the underlying formula is key to arriving at the correct answer below:

Concept: Internal energy components for different types of gases.
Formula: For monoatomic ideal gas, \( U = \frac{3}{2} nRT \) (translational only).
Solution: For an ideal monoatomic gas, internal energy is purely translational kinetic energy. General internal energy can have translational, rotational, vibrational, and potential contributions (for real/complex gases), but potential energy is zero for ideal gases. A is true, R is true but not an explanation for A.

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