Question

A negatively charged particle is moving to the right, directly above a wire have a current flowing to the right. In which direction is the magnetic force exerted on the particle?A) into the pageB) downwardC) upwardD) out of the page

Answer 1

Answer:

C) upward

Explanation:

The problem can be solved by using the right-hand rule.

First of all, we notice at the location of the negatively charged particle (above the wire), the magnetic field produced by the wire points out of the page (because the current is to the right, so by using the right hand, putting the thumb to the right (as the current) and wrapping the other fingers around it, we see that the direction of the field above the wire is out of the page).

Now we can apply the right hand rule to the charged particle:

- index finger: velocity of the particle, to the right

- middle finger: direction of the magnetic field, out of the page

- thumb: direction of the force, downward --> however, the charge is negative, so we must reverse the direction --> upward

Therefore, the direction of  the magnetic force is upward.