The frequency of radiations emitted when electron falls from `n = 4` to `n = 1` in `H-"atom"` would be (Given `E_1` for `H = 2.18 xx 10^-18 J "atom"^-1` and `h = 6.625 xx 10^-34 Js`.)

Options

A. `2.00 xx 10^(15)s^(-1)`
B. `1.54 xx 10^(15) s^(-1)`
C. `1.03 xx 10^(15) s^(-1)`
D. `3.08 xx 10^(15) s^(-1)`

Answer

D

Explanation

`I.E_(1) (H) = 2.18 xx 10^(-18) J`
`:. E_(1) = -2.18 xx 10^(-18) J`
`:. E_(4) = (-2.18 xx 10^(-18)J)/(4^(2))J`
`Delta E = 2.18 xx 10^(-18)(1-(1)/(16))J`
`= (2.18 xx 10^(-18) xx 15)/(16)J`
`v = (Delta E)/(h) = (2.18 xx 10^(-18) xx 15J)/(16 xx 6.25 xx 10^(-34)Js)`
`= 3.08 xx 10^(15) s^(-1)`