If the radius of the second Bohr of hydrogen atom is `r_(2)` the radius of the third Bohr orbit will be

Options

A. `(4)/(9) r_2`
B. `4 r_2`
C. `(9)/(4) r_2`
D. `9 r_2`

Answer

C

Explanation

( c) `r = (n^2 h^2)/(4 pi^2 m Ze^2)`
`therefore (r_2)/(r_3) = (2^2)/(3^2)`
`therefore r_(3) = (9)/(4) r_2`.