The first emission line of Balmer series in H spectrum has the wave number equal to :

Options

A. `(9R)/(400) cm^(-1)`
B. `(7R)/(144) cm^(-1)`
C. `(3R)/(4) cm^(-1)`
D. `(5R)/(36) cm^(-1)`

Answer

D

Explanation

For Balmer series `n_(1) = 2` and `n_(2) =3,4,5,……..` `bar(v)` (For first line)
`= R = ((1)/(2^(2))-(1)/(3^(2))) = R((1)/(4)-(1)/(9)) = (5R)/(36)cm^(-1)`