Write down the expression for the radii of orbits of hydrogen atom. Calculate the radius of the smallest orbit.

Explanation

The radius of the `n^(th)` orbit of a hydrogen atom is given by
`r = (n^(2)h^(2))/(4 pi ^(2) mKe^(2))`
Radius of innermost orbit, called Bohr.s radius, is obtained by putting n = 1. It is denoted by `r_(0)`
`r_(0) = (h^(2))/(4 pi^(2)mKe^(2)) = (6.6 xx 10^(-34))^(2)/(4 xx (3.14)^(2) xx 9.1 xx 10^(-31) xx 9 xx 10^(9) xx(1.6 xx 10^(-19))^(2))`
`r_(0) = 0.53 xx 10^(-10)m = 0.53 A ^(@)`.