The wave number of energy emitted when electron jumps from fourth orbit to second orbit in hydrogen in `20,497cm^(-1)`. The wave number of energy for the same trasition in `He^(+)` is

Options

A. `5,099cm^(-1)`
B. `20,497cm^(-1)`
C. `40,994cm^(-1)`
D. `81,988cm^(-1)`

Answer

D

Explanation

`bar(v)=RZ^(2)(1/n_(1)^(2)(-1)/n_(2)^(2))_,bar(v)aZ^(2)`