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Homework Help: A circulating charged particle under a magnetic field

  1. Oct 27, 2011 #1

    This is a chamber, immersed in a magnetic field, containing circulating electrons shot into a gas. My question is: why is the direction of rotation for the electrons (as shown on the picture) clockwise and not counterclockwise? I am crossing v with B, which is directed outward of the page, and so, Fb is directed toward the center of the circle. However, with the direction of v and Fb known, I would think the electrons circulate counter-clockwise. Why is this not the case?
  2. jcsd
  3. Oct 27, 2011 #2
    I applied the RHR and determined that the force on a positive charge is directed outwards from the balloon. Thus, the force reverses and points inwards for a negative charge.
  4. Oct 27, 2011 #3
    Also, it doesn't look like their rotating about the centre axis clockwise at all. To me, it appears that the velocity vector points in the direction such that the particles go counter clockwise.
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