A spinning question

  1. An electron has its spin vector pointing in the positive x-direction and a magnetic field vector is turned on in the positive z-direction.

    Question 1. Does the spin vector turn to the positive z-direction and start to precess around the z-axis? Or does is precess around the x-axis?

    Question 2. If the magnetic field vector is turned off, and the spin vector did turn to the positive z-direction does is go back to the x-direction? Or if it stayed pointing in the x-direction does it stop precessing?

    I think the answer to question 1 is that the spin vector point in the x-direction and starts to precess around the x-axis. The answer to question 2 is it stops the precession around the x-axis and stays pointing in the positive x-direction.
    Could someone please tell my if I'm right or wrong.









    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. It precesses about the z axis, and stops when B is turned off.
     
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