http://imageshack.us/photo/my-images/543/unledyel.png/ 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?