An electron and a proton are both initially moving with the same speed and in the same direction at 90˚ to the same uniform magnetic field.They experience magnetic forces, which are initially:
A)identical
B)equal in magnitude but opposite in direction
C)in the same direction and differing in magnitude by a factor of 1840
D)in opposite directions and differing in magnitude by a factor of 1840
E)equal in magnitude but perpendicular to each other

Question

Quizplus · Accepted Answer

The magnetic force on a charged particle is given by $F = qvB\sin(\theta)$, where $q$ is the charge, $v$ is the velocity, $B$ is the magnetic field strength, and $\theta$ is the angle between the velocity and the magnetic field. Since the electron and proton have equal and opposite charges and are moving at the same speed in the same direction relative to the magnetic field, the magnitudes of their forces will be equal, but the directions will be opposite due to their opposite charges.

An Electron and a Proton Are Both Initially Moving with the Same