The mangnitude of pontential energy of electron in `n^(th)` excited state of `He^(+)` ion is `(8)/(81)` time the kinetic energy of electron of excited state of `Li^(2+)` ion. Find `'n'`

Answer

`5`

Explanation

`E_(T) = -KE = (PE)/(2)`
`E_(T) = -13.6 xx (z^(2))/(n^(2)) ev`
`|PE_(n+1)` for `He^(+)| = (8)/(81) KE_(2)` for `Li^(2+)`
or `2 xx 13.6 xx (2^(2))/((n + 1)^(2)) = (8)/(81) xx 13.6 xx (3^(2))/(2^(2))`
or `n = 5`