Equal charges, one at rest, the other having a velocity of 104 m/s, are released in a uniform magnetic field. Which charge has the largest force exerted on it by the magnetic field?
A)The charge that is at rest.
B)The charge that is moving, if its velocity is parallel to the magnetic field direction when it is released.
C)The charge that is moving if its velocity makes an angle of 45o with the direction of the magnetic field when it is released.
D)The charge that is moving if its velocity is perpendicular to the magnetic field direction when it is released.
E)All the charges above experience equal forces when released in the same magnetic field.

Question

Quizplus · Accepted Answer

The charge that is moving with a velocity perpendicular to the magnetic field direction experiences the largest force. This is because the force experienced by a charged particle moving in a magnetic field is given by F=qvB*sin(theta), where q is the charge of the particle, v is its velocity, B is the magnetic field, and theta is the angle between the velocity and the magnetic field. Since sin(90°)=1, the force experienced by a charged particle moving perpendicularly to the magnetic field is the largest. Therefore, the charge that is moving with a velocity perpendicular to the magnetic field direction experiences the largest force.

Equal Charges, One at Rest, the Other Having a Velocity