The shape of $2p$ orbital is

How many electrons can be accommodated in a sub-shell for which $n = 3, l = 1$?

The ground state energy of a hydrogen atom is $-13.6 \ eV$. Consider an electronic state $\Psi$ of $He^+$ whose energy,azimuthal quantum number,and magnetic quantum number are $-3.4 \ eV$,$2$,and $0$ respectively. Which of the following statement$(s)$ is(are) true for the state $\Psi$?
$(1)$ It has $2$ angular nodes
$(2)$ It has $3$ radial nodes
$(3)$ It is a $4d$ state
$(4)$ The nuclear charge experienced by the electron in this state is less than $2e$,where $e$ is the magnitude of the electronic charge.

The degeneracy of the energy level of a hydrogen atom that has an energy of $\left(\frac{-R_{H}}{16}\right)$ is

$d_{z^2}$ orbital has :

The radial part of the wave function is determined by which quantum numbers?