The radius of innermost electron orbit of a hydrogen atom is $5.3×10^{-11} m$. What is the radius of n = 2 orbit?

$2.12×10^{-10} m$

The correct answer is Option (4) → $2.12×10^{-10} m$

In the Bohr Model of the hydrogen atom, the radius of n-th electron orbit is -

$r_n=r_1×n^2$  [$r_1$ = Radius of inner most circle]

$∴r_2=r_1×2^2$

$=5.3×10^{-11}×4$

$=2.12×10^{-10}m$