Question

In an atom two electrons move around the nucleus in circular orbits of radii r and 4r. The ratio of the time taken by then to complete one revolution around the nucleus is 

(1) 1/16

(2) 1/8

(2) 1/2

(3) 8

Answer 1

Correct option : (2) 1/8

Explanation : 

If the electron is moving with a velocity v around the nucleus the time taken by it to complete one revolution would be given by T = 2πr/v

Now from Bohr’s theory we have