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

Question

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

anonymous · Answer

The direction of magnetic force is the same as vextor v x B direction. It follows right hand rule, so postive x X positive z = negative y direction.

F=qE. The force direction follows magnetic field E direction. Hence a)

ghazi · Answer

$$F=q*(V*B)$$ take the cross product of the movement of electron and applied magnetic field

anonymous · Answer

there is no force acting on the particle in the second question as the magnetic force acts only on those particles which are in motion.

anonymous · Answer

use right hand rule

anonymous · Answer

@AERONIK : the magnetic force is changing (from zero then turned on).

anonymous · Answer

i did the right hand rule for the first one and got neg y as well. for the 2nd question, is it b? no net force?

anonymous · Answer

Actually yes I think its B