Question

Which quantum numbers must be the same for the orbitals that they designate to be degenerate in a many-electron system?

Answer 1

For the orbitals that designate to be degenerate in a many-electron system, the following quantum numbers should be equal:
1- principle quantum number (n) : this describes the most probable distance of the electron from the nucleus
2- orbital angular momentum quantum number (l) : this determines the shape of the orbital