I know the answer is \"down,\" but could someone explain why please? thanks. \"A
ID: 3896119 • Letter: I
Question
I know the answer is "down," but could someone explain why please? thanks.
"A velocity selector consists of a charged particle passing through crossed electric and magnetic fields. The forces exerted by these fields are in opposite directions, and only particles of a certain velocity will move in a straight line. In the following, disregard the magnitudes of the fields. In a velocity selector, the particles move toward the east, and the magnetic field is directed to the north. What direction should the electric field point?"
Why is it directed DOWN? Thanks!
Explanation / Answer
Using right hand rule, if you make your three mutually perpendicular axis using your right hand's thumb,index and middle fingure. Now point the index to the direction of velocity of particle and simultaneously point your middle finger along the direction of magnetic field, the thumb will show the direction of magnetics force, which comes out to be upward.
Thus as electrical field has to be opposite, thus has to be downward