An electron is traveling horizontally from E to W in a region of space where the Earth's magnetic field is directed horizontally toward the north.What is the direction of the magnetic force on the electron?

Question

Quizplus · Accepted Answer

The magnetic force on a charged particle is given by the cross product between the velocity of the particle and the magnetic field. As the electron is traveling horizontally from E to W, its velocity is towards the west. The magnetic field is towards the north. Therefore, the cross product gives a force upwards (out of the page).

An Electron Is Traveling Horizontally from E to W in a Region