In an atom two electrons move round the nucleus in circular orbits of radii R and 4R respectively, the ratio of time taken by them to complete one revolution is
$\dfrac{1}{4}$
$\dfrac{4}{1}$
$\dfrac{8}{1}$
$\dfrac{1}{8}$
In an atom two electrons move round the nucleus in circular orbits of radii R and 4R respectively, the ratio of time taken by them to complete one revolution is