New theories must in some approximation must reduce to older approximately correct theories. In what approximation exactly does the angular momentum quantization condition from Schroedinger's equation reduce to that of Bohr?
According to wave mechanics, $$L=\sqrt{\langle\hat{L}^2\rangle}=\sqrt{\ell(\ell+1)}\hbar$$ According to Bohr model,$$L=n\hbar.$$
I tried equating the two and expected that Bohr model will give one of the subshells, but got impossible relations between $n$ and $\ell$. In what mathematical approximation will the two $L$s coincide?