The correct option is B 3
Given: Transition in H -spectra where n1 = 1 and n2 = 5.
We know, Total number of spectral line = (n2−n1)(n2−n1+1)2
So, total number of lines = (5−1)(5−1+1)2 = 10
The 10 transitions possible are 5→4, 5→3, 5→2, 5→1, 4→3, 4→2, 4→1, 3→2, 3→1, 2→1.
Now, transitions in visible regions are when electron jumps from 5→2, 4→2, 3→2 i.e. in the visible region.
Three spectral lines will be obtained in the line spectrum.