PHYS 317 - Reading Assignment #4
Read section 2.1, and answer the following questions by email
hardcopy, or web form before class Monday, Sep 8.
- Flip two coins. What is the multiplicity of the macrostate defined
by getting one heads and one tails? What is the probability of getting this
multiplicity=2. Probability = multiplicity of 1 heads and 1 tails divided by
the total multiplicity, so 2/4 = 1/2.
- Flip 10 coins. What is the multiplicity of the macrostate with 9
With 9 heads and 1 tails, the tails result could have been the 1st coin, 2nd
coin, 3rd coin, etc, so there are 10 different ways to get the result.
- What is the numerical value of ``6 choose 2''?
6!/(2! 4!) = 720/(2*24) = 15
- Suppose I flip a few hundred coins, and want to use the result as an
analogy for a two-state paramagnet. How would I determine my system's energy
by looking at the coins?
The heads would be analogous to a spin aligned with the B field and tails
a spin anti-aligned (or vice versa). So the ``energy'' would be determined
by the difference between the number of heads and the number of tails.
- Was there anything you had particular difficulty with in this
reading? Is so, describe briefly.
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