1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Motion of a charged particle in a uniform magnetic field

  1. Apr 2, 2012 #1
    See attachment.

    I don't why a charged particle in a uniform magnetic field will move in a circle. Why can't it just continue straight in the direction its going until another force acts on it?

    Attached Files:

  2. jcsd
  3. Apr 2, 2012 #2
    ok, I'm starting to think that it's just a brute fact. that's just the way particles behave in a magnetic field and no explanation can be offered.
  4. Apr 2, 2012 #3


    User Avatar
    Science Advisor
    Homework Helper

    hi bobsmith76! :smile:

    but that F force in your diagram is always sideways …

    if you believe the diagram, then how can the particle go straight when there's a sideways force on it? :confused:
  5. Apr 2, 2012 #4
    Think of it like this, the particle is feeling the force on the side, it makes it turn (but the velocity will not change). So now consider the same particle in a new point in the system, your particle has turned for a little bit, and now still feels the force on it's side, which will make it continue to turn.

    Now do this for all following points that exist in it's path, and you will see it will continue to move in a circle.

    As the diagram says, the force is always perpendicular to the direction it's moving.

    Think of a centripetal force, if that makes it more easy.
  6. Apr 2, 2012 #5
    ok, i get it now. thanks.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook