The electron in a hydrogen atom jumps from ground state to the higher energy state where its velcoity is reduced to one-third its initial value. If the radius of the orbit in the ground state is `r` the radius of new orbit will be

Options

A. 3 r
B. 9 r
C. `( r)/(3)`
D. `( r)/(9)`

Answer

B

Explanation

`v = (1)/(137) (c)/(n) or v prop (1)/(n)`
Since `v` is reduced to one - third, therefore
`n = 3`
Now, `r prop n^(2)`