Question

If the energy of a hydrogen atom in `nth` orbit is `E_(n)`, then energy in the nth orbit of a singly ionised helium atom will be
A. `4 E_(n)`
B. `E_(n)//4`
C. `2E_(n)`
D. `E_(n)//2`

Answer 1

Correct Answer - A
`E_(n) prop Z_(2) rArr ((E_(n))_(H))/((E_(n))_(H)) = (Z_(He)^(2))/(Z_(H)^(2)) = 4 rArr (E_(n))_(He) = 4 xx (E_(n))_(H)`