The ratio between acceleration of the electron in singly ionised helium atom and doubly ionised lithium atom (both in ground state ) is

Options

A. `(4)/(9)`
B. `(27)/(8)`
C. `(8)/(27)`
D. `(9)/(4)`

Answer

C

Explanation

`a=(v^(2))/(r) or a prop ((Z)^(2))/((1//Z))`
`" " aprop Z^(3)`
For singly ionised helium atom, Z=2
and doubly ionised lithium atom Z=3
`rArr" " (a_(He))/(a_(Li))=((2)^(3))/((3)^(3))=(8)/(27)`