Using known values for hydrogen atom, calculate speed of electron in fourth orbit of `He^(+)`

Explanation

As Z=2 for `He^(+)`. Also we know that `v_(n)=(Z)/(n)v_(1)`
Substituting n=4,Z=2 and `v_(1)=2.19xx10^(6)ms^(-1)`, we get
` v_(4)=((2)/(4))(2.19xx10^(6))ms^(-1)`
`=1.095xx10^(6) ms^(-1)`