Which of the following is(are) correct for H atom ?
`1s lt 2s lt 2p lt 3s lt 3p`
`1s lt 2s = 2p lt 3s = 3p`
`1s lt 2p lt 3d lt 4s`
`1s lt 2s lt 4s lt 3d`
The correct choice is

Options

A. ii,iii
B. I,iv
C. I,iii
D. ii,iv

Explanation

To determine which of the given statements about the hydrogen atom are correct, we need to analyze the energy levels of the orbitals based on the principles of quantum mechanics. The energy levels of the orbitals are influenced by the principal quantum number (n) and the azimuthal quantum number (l).

### Step-by-step Solution:

1. **Understanding the Energy Levels**:
- The energy of an electron in an atom increases with the principal quantum number (n). For hydrogen, the energy levels are determined solely by n because there is only one electron.
- For orbitals with the same principal quantum number (n), the energy levels can be affected by the azimuthal quantum number (l). Generally, for a given n, the order of energy levels is:
- s < p < d < f (where l = 0 for s, l = 1 for p, l = 2 for d, and l = 3 for f).
...