Question

In a collection of $H-atoms$, all the electrons jump from n=5 to ground level finally (directly or indirectly), without emitting any line in Balmer series. The number of possible different radiations is:

Answer 1

Total number of lines = $\frac{(n_2-n_1)(n_2-n_1+1)}{2}=\frac{(5-1)(5-1+1)}{2}$= 10

Possible Balmer lines are = $5\to 2,4\to 2,3\to 2$
Since there are no Balmer lines observed, the transition $2\to 1$ is also not possible.
Therefore, total number of possible different radiation = 10 - 4 = 6