# How are length and time scales for the different kinds of interactions (strong, weak, electroweak) determined?

I was recently asked what the length scale of the strong interaction is and found my self a bit lost at the question. A quick Google search revealed a result of $$10^{-15}\,\text{m}\approx 1\,\text{GeV}$$ (see here) but I'm still wondering how I could derive this...

Is there a ''quick'' way to determine the time and length scales for the weak-, strong-, electromagnetic- and maybe even the electroweak-interaction? What do I need to know to derive it?

A possible solution to this question (or at least to the length scale part) might be section 1.2.1, or to be more precise eq. (1.13), but I'm having a bit of a hard time understanding how the author reaches this result and why it makes sense..

• For the lengths these are experimental facts, though you can rediscover them from the theories that are used to describe the experimental results. (BTW, you should be careful when talking about the strong interaction to distinguish between the bare interaction and the effective nuclear interaction.) Time scales are more complicated, you can just divide your length scale by $c$, but then you have to ask what to expect that time to mean and the answer is not always as useful as you would hope. – dmckee Jun 27 at 22:49