A proton, moving west, enters a magnetic field. Because of this magnetic field the proton curves upward. We may conclude that the magnetic field must have a component
A) towards the west.
B) towards the north.
C) towards the south.
D) towards the east.
E) downward.

Question

Quizplus · Accepted Answer

The magnetic force on a charged particle is perpendicular to both the velocity of the particle and the magnetic field. Since the proton curves upward, the magnetic field must have a component towards the south to create a force that is perpendicular to the westward velocity and results in an upward deflection.

A Proton, Moving West, Enters a Magnetic Field