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Homework Help: Representation of quantum numbers +1/2 and -1/2

  1. Aug 12, 2012 #1
    1. The problem statement, all variables and given/known data
    The quantum numbers +1/2 and -1/2 for the electron spin represents?

    2. Relevant equations
    a) rotation of electron in clockwise and anticlockwise directions respectively
    b) tow quantum mechanical spin states which have no classical analogue
    c) Magnetic moment of electron pointing up and down respectively
    d) Rotation of electron in anticlockwise and clockwise directions respectively

    3. The attempt at a solution
    Since the term "respectively" is used in the options a) and d), the option d) cancels out and even i think the option c cancels out also.

    I am confused between the a) and b) one,
    what does one mean by classical analogue?
  2. jcsd
  3. Aug 13, 2012 #2


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    Gold Member

    No Classical Analogue simply means that there is no equivalent phenomena which can describe the Spin Quantum number in Classical Physics - one which we usually study. It is a quantity dedicated to only atomic level in Modern Physics. Therefore, you can't say that the electron is spinning clockwise or anticlockwise like we say for objects.

    So, the answer in my opinion is (B).
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