# Homework Help: Basic Statistical Mechanics question

1. Dec 19, 2012

### ZedCar

1. The problem statement, all variables and given/known data

An isolated system has N=3 distinguishable particles A, B, C with single particle states equally spaced at intervalsof E and a total energy U=3E.
ie the macrostate is defined by N=3, U=3E.

The system has single particle levels 0, E, 2E, 3E.

2. Relevant equations

3. The attempt at a solution

The beginning of the solution then begins with:

ni = {2, 0, 0, 1}
{1, 1, 1, 0}
{0, 3, 0, 0}

How were these sets of number obtained?

Thanks for any help!

2. Dec 19, 2012

### clamtrox

These are the possible microstates. For {2, 0, 0, 1} , you have two particles with energy ε=0 and one particle with ε=3E, so Ʃεi = 3E, as it should. For {1, 1, 1, 0}, one particle has ε=0, second has ε=E and third has ε=2E. For {0, 3, 0, 0} all particles have energy E. You should be able to convince yourself that these are the only possibilities to get total energy of 3E.