# Homework Help: Calculate the energy spread of the Fe-57 first excited state

1. Feb 24, 2013

### richyw

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

Calculate the energy spread of the 57Fe first excited state, which has energy 14.4 keV and lifetime 141 ns.

2. Relevant equations

$$\Gamma\tau=\hbar$$

3. The attempt at a solution

No idea what this is really asking me. is it really just
$$\Gamma=\frac{\hbar}{\tau}$$
assuming it's not because it gave the energy...

2. Feb 24, 2013

### Staff: Mentor

Is the energy used in any follow-up question?
Otherwise, I think it is irrelevant. Lifetime alone gives the energy spread.

3. Feb 24, 2013

### richyw

nope, it was a single question. Guess it was a trick. Thanks.

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