Which of the following $p, d, f$ orbitals are not possible? Why?

The orbital angular momentum of a $3p$ electron is

Which of the following orbitals are degenerate? $3d_{xy}, 4d_{xy}, 3d_{z^2}, 3d_{yz}, 4d_{yz}, 4d_{z^2}$

For which of the following sets of quantum numbers,an electron will have the highest energy?

Explain the meaning of the $+ve$ and $-ve$ signs in the context of the wave function $\psi$ for an electron.

The quantum numbers of six electrons are given below. Arrange them in order of increasing energies. If any of these combination$(s)$ has/have the same energy,list them:
$(1).$ $n=4, l=2, m_l=-2, m_s=-1/2$
$(2).$ $n=3, l=2, m_l=1, m_s=+1/2$
$(3).$ $n=4, l=1, m_l=0, m_s=+1/2$
$(4).$ $n=3, l=2, m_l=-2, m_s=-1/2$
$(5).$ $n=3, l=1, m_l=-1, m_s=+1/2$
$(6).$ $n=4, l=1, m_l=0, m_s=+1/2$