Number of possible spectral lines in the bracket series in hydrogen spectrum, when electrons present — Atomic Structure Chemistry Question

💡 Solution & Explanation

The ninth excited state corresponds to principal quantum number $n = 10$. The Brackett series consists of transitions that terminate at $n=4$. The possible initial states for Brackett series emission from electrons starting at $n=10$ are $10, 9, 8, 7, 6, 5$. This gives $10 - 4 = 6$ possible spectral lines. Therefore, correct answer is D.