The ionisation energy of `He^(o+)` is `19.6 xx 10^(-18) J atom^(-1)` .The energy of the first stationary state of `Li^(2+)` will be

Explanation

We know,
` E-1 " for " Li^(2+) = E_1 "for " H xx 9`
` E_1 " for " He^+ = E_1 " for" Hxxx 4`
` E_1 " for " Li^(2=) = E_1 " for " He^+ xx 0/4`
` = 19. 6 xx 10^&(-18) xx 9/4`
` = 44 . 1 xx 10^(18) "J atom"^(-1)`.