In hydrogen atom, electron makes transition from `n = 4` to `n = 1` level. Recoil momentum of the `H` atom will be

Options

A. `3.4xx10^(-27) N-s`
B. `6.8xx10^(-27) N-s`
C. `3.4xx10^(-24) N-s`
D. `6.8xx10^(-24) N-s`

Answer

D

Explanation

`(1)/(lambda)=Z^(2)R((1)/(n_(1)^(2))-(1)/(n_(2)^(2)))=R ((1)/(1^(2))-(1)/(4^(2)))=(15R)/(16)`
`0=-p+(h)/(lambda) implies p=(h)/(lambda)=(h)/(15 R//16)=(16 h)/(15 R)`
`p=(16xx6.6xx10^(-34))/(15xx1.097xx10^(-7))=6.4xx10^(-27) N-sec`