The hydrogen atom is excited from ground state to a state with the principal quantum number (n) = 4. The number of spectral lines in the emission spectra will be
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 6
From the level \( n = 4 \) the atom can return to the ground state directly or in steps, and every possible transition between two levels gives one spectral line. The number of lines from level \( n \) is
\( \displaystyle N = \frac{n(n-1)}{2} = \frac{4\times3}{2} = 6 \)
The lines are \( 4\to3,\ 4\to2,\ 4\to1,\ 3\to2,\ 3\to1,\ 2\to1 \).