Answer: qB/(2pi m).
- A qB/(2pi m)
- B 2pi m/(qB)
- C qm/B
- D qB m/2pi
Correct answer: A. qB/(2pi m)
Explanation: Cyclotron frequency f = qB/(2 pi m). It depends on charge, mass, and field but NOT on speed (for non-relativistic particles).
The magnetic field around a long straight current-carrying wire forms concentric circles, with direction given by the right-hand rule (point thumb along I, fingers curl in the direction of B).
Concept context
Magnetic force on moving charges and currents, the Biot-Savart law, Ampere's law, and the cyclotron - how electric currents create and respond to magnetic fields.