Question

The answer to each question of this set is a single digit integer, ranging from 0 to 9:

How many Balmer lines in the spectrum will be observed when electrons return from 7th shell to 2nd shell ?

Answer 1

There were five lines observed in balmer series when electron jumps from 7 to 2
Those are 7->2,6->2,5->2,4->2,3->2.