The radius of hydrogen atom in its ground state is `5.3xx10^(-11)m`. After collision with an electron it is found to have a radius of `21.2xx10^(-11)m`. What is the principal quantum number n of the final state of atom ?

Options

A. 1
B. 2
C. 3
D. 4

Answer

B

Explanation

`r_(n) prop n^(2)`
`(n^(2)/(n^(2)) = (21.2 xx 10^(-11))/(5.3 xx 10^(-11)))` or `(n^(2)/(n^(2))) = 4`
or `(n^(2)/(1^(2))) = 4` or `n = 2`