The wavelength (in Å) of an emission line obtained for `Li^(2+)` during an electronic transition `n_(2) = 2` and n = 1 is (R = Rydberg constant)

Options

A. `3R//4`
B. `27R//4`
C. `4//3R`
D. `4//27 R`

Answer

D

Explanation

`bar(nu) = R((1)/(n_(1)^(2))-(1)/(n_(2)^(2))) Z^(2) = R((1)/(1^(2))-(1)/(2^(2))) xx 3`
`= R[(4-3)/(4)] xx 3^(2) = (27 R)/(4)`
`:. lambda = (1)/(nu) = (4)/(27 R)`