Question

Find maximum no. of spectral lines in visible region of hydrogen sample when electrons jumps from 6th excited state to ground state?

• A. 7
• B. 5
• C. 15
• D. 21

Answer 1

Answer: (B)

5

Answer 2

The 6th excited state corresponds to $n=7$. The visible region of the hydrogen spectrum (Balmer series) involves transitions ending at $n_f=2$. The possible transitions from $n=7$ to $n_f=2$ are $7 \to 2$, $6 \to 2$, $5 \to 2$, $4 \to 2$, and $3 \to 2$. The number of such transitions is $7 - 2 = 5$.