# Beta decay, electron capture Q value

1. Apr 30, 2016

### Incand

1. The problem statement, all variables and given/known data
Find the $Q$ value for electron capture of $^{196}Au$.

2. Relevant equations
$Q_\epsilon = [m(^AX)-m(^AX')]c^2-B_n$

3. The attempt at a solution
How do I know if I have an $K$- or $L$-shell for the electron?
Assuming I have an $K$ shell taking $B_n = \; ^{196m1}Au$ from this table,
https://en.wikipedia.org/wiki/Isotopes_of_gold
;I get the correct answer but I don't understand why it couldn't just as well been an $L$-shell?

2. Apr 30, 2016

### Staff: Mentor

Capture from the innermost shell is by far the most likely process.

3. Apr 30, 2016

### Incand

Thanks! That would make sense out of it.