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A particle with mass m and charge q moves in a circle of radius r in a plane perpendicular to a magnetic field of magnitude B. The period of one complete revolution is

1. 2πq²B/m
2. 2πmq/B
3. 2πm/qB
4. 2πqB/m

Correct answer: 2πm/qB

Solution

The period of revolution for a charged particle in a magnetic field is derived from the balance of the magnetic force and the centripetal force, leading to the formula T = 2πm/(qB), where T is the period, m is the mass, q is the charge, and B is the magnetic field strength.

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