The radius of H atom in its ground state is `0.53 Å` After collision with an electron, its radius is found to be `21.2 xx 10^(-11)m`. In this state, the principle quantum number 'n' of the H-atom is

Options

A. 2
B. 3
C. 4
D. 16

Answer

A

Explanation

`r_(n)=r_(1) n^(2)`
`:. n^(2)=r_(n)/r_(1)=(21.2xx10^(-11))/(0.53xx10^(-10))=4`
`:. n=2`