Question

If the electron in the hydrogen atoms is excited to n = 5 state, the number of frequencies present in the radiation emitted is :

• A. 4
• B. 5
• C. 8
• D. 10

Answer 1

The correct option is D 10

The given excited state $n=5$
Thus number of frequencies (or spectral lines) $N=\frac{n(n-1)}{2}$
$⟹N=\frac{5\times (5-1)}{2}=10$