Compare the interaction of charged particles moving in magnetic fields

Movement of charged particle in:

	Electric field	Magnetic field
FORCE	direction and magnitude of force due to electric field is independent of velocity of charged particle	direction of force due to magnetic field is perpendicular to the direction of the velocity of the charged particle and the magnitude of force is directly proportional to the magnitude of the velocity
ACCELERATION	The acceleration produced by force due to electric field is independent of velocity of charged particle	The acceleration produced by force due to magnetic field is perpendicular to the direction of the velocity of the charged particle and the magnitude of acceleration is directly proportional to the magnitude of the velocity
ENERGY	As Electric field does work on the charged particle as it moves, there is change in Kinetic and Potential energy.	As magnetic field does no work on the charged particle as it moves, there is no change in Kinetic and Potential energy.

Circular motion :

Force on moving charge due to a magnetic field: F = qvB
Since the force is always perpendicular to the velocity , it can act as centripetal force for circular motion.
Centripetal force for uniform circular motion:
therefore,
Thus the radius of path of uniform circular motion, of a moving charged particle depends on mass, charge and velocity of the particle and strength of the magnetic field.