Motion of an electron in a uniform eld An electron (mass m, charge e) moves in a uniform magnetic eld l : Bok. At t = 0, the electron's velocity is 6(0) : vocal + vyoj. Bo and 0330 are positive but vyo is negative. The electron subsequently moves along a circular path. Ignore any forces on the electron other than the magnetic force. (a) What is the magnetic force on the electron at t : 0? (b) If looking in the z direction (so +k is pointing toward you), does the electron circulate clockwise or counterclockwise? Explain. (c) What is the radius of the circle? (d) Suppose now that the electron also had an initial zcomponent of velocity: 9(0) 2 1Jle + 12ij + 11201:: where 1130 is positive. In that case, the electron would move along a helical path with the same radius as before. What is the pitch of the helix? (The pitch is the distance moved along the magnetic eld direction during one revolution of the electron.)