Physics Class 11 Chapter 13. Kinetic Theory | Page 6

Degree of Freedom
The degree of freedom for a dynamic system is the number of directions in which it can move freely or the number of coordinates required to describe completely the position and configuration of the system.
It is denoted by for N. Degree of freedom of a system is given by f or N = 3A – R
where A = number of particles in the system and R = number of independent relations.
Degree of Freedom
1. For monoatomic gas = 3 2. For diatomic gas = 5