Question

At a given moment the particle is moving in the x direction (and the magnetic field is always in the z direction). If q is positive, what is the direction of the force on the particle due to the magnetic field?

Answer 1

Answer:

(-y)-direction.

Explanation:

The force created by the magnetic field on a moving object is

$\vec{F}_B = q\vec{v} \times \vec{B}$

So the directions are

$\vec{F}_B = \^x \times \^z = -\^y$

The direction can also be found by the right-hand rule.

Point your index finger in the direction of velocity. Point your middle finger in the direction of magnetic field. Your thumb will point towards the direction of the force.