What is the maximum number of emission lines when the excited electron of a H atom in `n = 6` drop to the ground state?

Explanation

When the excited electron of an H atom in n = 6 drops to the ground state, the following transitions are possible:
Hence, a total number of (5 + 4 + 3 + 2 + 1) 15 lines will be obtained in the emission spectrum.
The number of spectral lines produced when an electron in the nth level drops down to the ground state is given by
`(n(n-1))/2`
given
n=6
number of spectral lines ` = (6(6-1))/2 = 15`