A proton is traveling horizontally east in the magnetic field of Earth near the equator. The direction of the force on the proton is

Question

Quizplus · Accepted Answer

The force on a charged particle moving in a magnetic field is given by the cross product of the velocity of the particle and the magnetic field vector. As the proton is traveling horizontally east, its velocity is directed to the east. Near the equator, the Earth's magnetic field is directed downward, so the magnetic field vector points downward. The cross product of eastward velocity and downward magnetic field results in a force directed upward.

A Proton Is Traveling Horizontally East in the Magnetic Field