I am trying to find the most probably distance of the electron from the nucleus of a ground state hydrogen atom. The wave function is given as the following:
$$\psi_{1,0,0}(r,\theta,\Phi)=R_{1,0}(r) \cdot Y_{1,0}(\theta, \Phi)$$
I remember that the probability function is $\psi^2$, but why do...