An electron has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. This magnetic field must have a component
A) to the west.
B) downward.
C) to the north.
D) to the east.
E) upward.

Question

Quizplus · Accepted Answer

The magnetic force on a moving electron is given by the Lorentz force equation: F = q(v x B), where q is the charge of the electron, v is its velocity, and B is the magnetic field. The cross product of two vectors is a vector that is perpendicular to both of the original vectors. In this case, the velocity of the electron is to the south and the magnetic field is to the west, so the Lorentz force will be upward.

An Electron Has an Initial Velocity to the South but Is