Question

The number of possible lines of Paschen series when an electron jumps from the $7^{th}$ excited state to the ground state in a hydrogen like atom is:

• A. 2
• B. 5
• C. 4
• D. 3

Answer 1

The correct option is B 5

$n_1$ for the Paschen series is 3.
$n_2$ for the 7${}^{th}$ excited state is 8.
Number of lines of Paschen series, $n_2-n_1=8-3=5(8\to 3,7\to 3,6\to 3,5\to 3,4\to 3)$