# Entropy of a quantum sized material

1. Dec 8, 2011

### phoenix133231

1. The problem statement, all variables and given/known data
A small material has quantum oscillator energy levels 2E-23 J apart. Suppose the material has a total energy of 34E-23 J and contains 5 atoms. Find the entropy of the material.

2. Relevant equations
Entropy = (Boltzmann's constant)*ln(multiplicity)

Multiplicity = (q + N - 1)!/[q!(N-1)!]

3. The attempt at a solution
I'm having trouble grasping the question. The 5 atoms are understood, but I'm having trouble finding the "N" for the multiplicity equation.

So, I came up with N = 18, because the total energy is 34E-23 J and the energy levels are 2E-23 J apart, and q = 5.

Then applying the multiplicity equation and plugging it to entropy, I didn't get the correct answer.

Am I on the correct path to find N, or do I even need the multiplicity equation?

2. Dec 9, 2011

### phoenix133231

Anyone, please?

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