Question

What is the maximum number of emission lines when the excited electron of a hydrogen atom in an equal to 4 drops to the ground state?

Answer 1

Yes, clearly there are eight spectral lines that can be drawn when an electron makes a transition from n=4 to ground state in four different cases (as in the diagram). But there is the repetition of spectral lines in case 2 (second line) and in case 3 (first line). So these two lines cannot be counted. So there are 6 spectral lines not 8.