JEE Physics · Hard

Magnetism: Cyclotron Resonance Condition MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

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Cyclotron Resonance ConditionHardQuestion 20225

Question

The cyclotron resonance condition breaks down when:
  1. A
    The particle speed exceeds the cyclotron critical speed
  2. B
    The particle's mass increases due to relativistic effects and the cyclotron frequency shifts
    Correct
  3. C
    The electric field frequency is too low
  4. D
    The magnetic field is too weak

Correct answer

The particle's mass increases due to relativistic effects and the cyclotron frequency shifts

Explanation

Cyclotron frequency f = qB/(2πm). At relativistic speeds, m increases → f decreases → the particle falls out of phase with the fixed-frequency alternating field. The synchrotron resolves this by adjusting the field frequency or B to maintain resonance.