# How do you calculate the strong isospin of nucleons?

First post, so hi everyone.

I have been banging my head against this question for a little while now. I've found two methods that appear to give the same result, but am not quite happy with what I've done:

## Homework Statement

Calculate the strong isospin components of both tritium (3H) and helium-3 (3He)

## Homework Equations

I've found two equations that give this value:

Iz = q/e - (S+B)/2

and

Iz = 1/2((nup - nantiup)- (ndown - nantidown))

## The Attempt at a Solution

Both of those give the result Iz = 3/2 for tritium and 1/2 for helium-3. However, the question tells me that both of them have total isospin I = 1/2. I was under the impression that Iz couldn't exceed I.

Am I wrong? Or have I got one of the calculations wrong?

EDIT: Oops- I think I see what I've done wrong. I assumed that 3H has 3 protons, when it obviously doesn't. Which makes me, well, an idiot.

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