[10 marks] Calculate
(:r:)(where
hat(r)=rfor a H atom in the
2p_(z)orbital. The normalized wavefunction
\psi _(2p_(t))(r,\theta ,\phi )is,
\psi _(2p_(t))(r,\theta ,\phi )=(\sqrt(2))/(4\sqrt(2\pi ))((1)/(a_(0)))^((3)/(2))(r)/(a_(0))e^(-(r)/(2)\theta )cos(\theta )