Question

If a steady magnetic field exerts a force on a moving charge, that force is directed

A) opposite the motion.
B) in the direction of the motion.
C) at right angles to the direction of the motion

Answer 1

C) at right angles to the direction of the motion

Step-by-step explanation:

The magnetic force exerted on a charged moving particle is given by

`F=qvBsin \theta`

where

q is the charge of the particle

v is the velocity of the particle

B is the magnetic field intensity

`\theta` is the angle between the direction of v and B

Moreover, the direction of the force is perpendicular to both v and B. In particular, the direction can be found by using the right hand rule:

- index finger: direction of the velocity

- middle finger: direction of the magnetic field

- thumb: direction of the force (if the charge is positive, otherwise the direction must be reversed if the charge is negative)