Conservative forces: If the work done by a force in moving a body between two positions is independent of the path followed by the body. then such a force is called as a conservative force. Examples: force due to gravity, spring force and elastic force. The work done by the conservative forces depends only upon the initial and final position of the body.
ɸ F . dr = 0
The work done by a conservative force around a closed path is zero.
Non conservative forces: Non-conservative force is the force, which can perform some resultant work along an arbitrary closed path of its point of application.
The work done by the non-conservative force depends upon the path of the displacement of the body.
ɸ F . dr ≠ 0
Example: Frictional force, Viscous Force etc.