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Homework Help: Energy of a magnetic dipole moment

  1. Oct 30, 2013 #1
    1. The problem statement, all variables and given/known data
    The z component of the magnetic dipole moment due to the spin of an electron about its axis is μz = +/- eh/4∏m, where h = 6.63 x 10-34 J s is Planck's constant. A) If μz is parallel to a magnetic field of 10 T, how much energy in electron volts must be supplied to reverse its direction so that it is opposite to the field?

    B) Find the ratio of this energy to the 13.6 eV needed to remove an electron from a normal hydrogen atom.

    2. Relevant equations

    μz = +/- eh/4∏m

    (μ) (2B)/h = V

    3. The attempt at a solution

    First find μz:

    μz = (+/- 1.60 x 10-19 C) (6.63 x 10-34 Js/ (4∏) (9.11 x 10-31 kg)

    μz = 9.30 x 10-24 Am2

    Find V:

    μ = hV/2 B

    V = (μ) (2B)/h = (9.30 x 10-24 Am2) (2 * 10 T)/(6.63 x 10-34 J s)

    V = 2.81 x 106 V

    B) (2.81 x 106 V)/(13.6 V) = 2.07 x 105

    Is this correct?
  2. jcsd
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