Question $5$

If protons are moving counterclockwise in a CYT positioned parallel to the page, in what

direction must the magnetic field be pointing?

xx A$.$ Points out of the plane $($towards the observer$)(49\%)$

B$.$ Points to the right $($in the plane of the screen$)(15\%)$

C$.$ Points into the plane $($away from the observer$)(27\%)$

D$.$ Points to the downward $($in the plane of the screen$)(9\%)$

Topic: Electrostatics & Magnetism, CC$4$C$,$ P$1$

You selected A I C is correct

Correct Answer: Choice C

This question asks for the direction of the magnetic field needed in a cyclotron to

confine protons moving in a counter$-$clockwise circular path. To answer this

question, we must recall our background knowledge of the right$-$hand rule for

magnetic force.

Charged particles $($like protons$)$ experience a force due to a magnetic field in a

direction perpendicular to both the particle's velocity and the magnetic field itself.

I know the right$-$hand rule, I just don't understand how to apply it to this question! Thanks!