An excited `He^(+)` ion emits photon of wavelength `lamda` in returning to ground state from `n^(th)` orbit. If ʻR’ is Rydberg constant, then

Options

A. `n= sqrt((4 lambda R)/(4lambda R-1))`
B. `n=sqrt((4lambdaR)/(4lambdaR +1))`
C. `n= sqrt((4lambdaR-1)/(4lambda R))`
D. `n= sqrt((4lambdaR+1)/(4lambda R))`

Answer

A

Explanation

`(1)/(lambda)=R xx 2^(2)[(1)/(1) -(1)/(n^(2))] rArr (1)/(lambda)= 4R [(n^(2)-1)/(n^(2))]`
`(1)/(n^(2))=(4lambdaR-1)/(4lambdaR) rArr n= sqrt((4lambdaR)/(4lambdaR-1))`