Number of spectral lines in balmer series when an electron return from 7 th orbit to 1st orbit of hydrogen atom are.......( Plzzzzz show calculation)

Number of spectral lines in balmer series when an electron return from

1.	Number of spectral lines in balmer series when an electron return from 7 th orbit to 1st orbit of hydrogen atom are.......( Plzzzzz show calculation)
Answer» (7-1)(7-1+1) /2 (6)(7) /2 42/2 21 this is total no of SPECTRAL line spectral line for balmer SERIES = (7-2) =5