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An electron and a proton, each with the same momentum, enter a uniform magnetic field at right angles to the field. What will be the nature of their paths?

1. Their trajectories will have the same curvature, apart from the direction of rotation.
2. Neither particle will be deflected.
3. The electron’s trajectory will be more sharply curved than the proton’s.
4. The proton’s trajectory will be more sharply curved than the electron’s.

Correct answer: Their trajectories will have the same curvature, apart from the direction of rotation.

Solution

Both the electron and the proton experience the same magnetic force due to their equal momentum and perpendicular entry into the magnetic field, resulting in circular paths. However, the electron, being lighter, will have a faster angular velocity, leading to the same curvature but opposite rotation direction.

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