In which direction does a magnetic force act on an electron that is moving in the positive x-direction in a magnetic field pointing in the positive z-direction?

a) any direction in the xy-plane
b) the negative y-direction
c) the negative x-direction
d) the positive y-direction

a particle with charge q is at rest when a magnetic field is suddenly turned on. the field
points in the z-direction. what is the direction of the net force acting on the charged particle?

a) in the z-direction.
b) there is no force on the particle.
c) in the y direction
d) in the x direction