A gaseous mixture contains hydrogen atoms in the 4^(th) excited state, He^(+) ions in 3^(rd) excited state and Li^(2+) in 2^(nd) excited state. The number of spectral lines obtained in the emission spectrum of this sample when all these atoms/ions return to the ground state is

A gaseous mixture contains hydrogen atoms in the 4^(th) excited state,

1.	A gaseous mixture contains hydrogen atoms in the 4^(th) excited state, He^(+) ions in 3^(rd) excited state and Li^(2+) in 2^(nd) excited state. The number of spectral lines obtained in the emission spectrum of this sample when all these atoms/ions return to the ground state is
Answer» <html><body><p>19<br/>20<br/>16<br/>18</p>Answer :D</body></html>