The radius of hydrogen atom in its ground state is `5.3 xx 10^-11 m`. After collision with an electron it is found to have a radius of `21.2 xx 10^-11 m`. The principal quantum number of the final state of the atom is.

Options

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

Answer

B

Explanation

`rpropn^(2)i.e.,(""^rf)/(r_(i))=((n_(f))/(n_(i)))^(2)`
`rArr " " (21.2xx2xx10^(-11))/(5.3xx10^(-11))=((n)/(1))^(2)rArrn^(2)=4rArrn=2`