The Balmer series in the hydrogen spectrum corresponds to the transition from ` n_(1)=2` to `n_(2)=3,4`........ This series lies in the visible region. Calculate the wave number of line associated with the transition in Balmer series when the electron moves to n=4 orbit.
`(R_(H)=109677cm^(-1))`

Explanation

`barv=109677[(1)/(n_(1)^(2))-(1)/(n_(2)^(2))]cm^(-1)`
For `n_(2)=4" to "n_(1)=2` transition in Balmer series.`" "therefore" "barv=109677[(1)/(2^(2))-(1)/(4^(2))]cm^(-1)`
`=109677[(1)/(4)-(1)/(16)]cm^(-1)=20564.44mc^(-1)`