If the radius of inner most electronic orbit of a hydrogen atom is `5.3xx10^(-11)` m, then the radii of `n=2` orbit is

Options

A. `1.12 Å`
B. `2.12 Å`
C. `3.22 Å`
D. `4.54 Å`

Answer

B

Explanation

As,`r_n=n^2a_0`
Here,`a_0=5.3xx10^(-11)m`,`n=2`
`therefore r_2=(2)^2a_0=4a_0=4xx5.3xx10^(-11)m`
`=21.2xx10^(-11)m=2.12Å`.