Question

What is ratio of radii of the orbits corresponding to first exhibted state and ground state in the hydrozen atom?

Answer 1

Radius of the nth orbit is given as

rn=(n2/m)(h/2π)2 (4πϵ0/e2)

For the ground state, n=1

For excited state, n=2

So the ratio between radii of the first orbital & the ground state radii is 4.