What is the ratio of radii of orbits corresponding to first excited state and ground state in hydrogen atom?

Options

A. `1:2`
B. `2:1`
C. `8:1`
D. `1:4`

Answer

C

Explanation

`T=(2pir)/(v) "But " r prop n^2 " and " v prop 1/n`
`therefore T prop n^2 xx n " or " T prop n^3`
`therefore (T_2/T_1) = (2/1)^3 = 8/1`