The kinetic energy of the electron in an orbit of radius r in hydrogen atom is proportional to ( e = electronic charge)

Step-by-step solution

In a hydrogen atom, the electrostatic force of attraction between the nucleus and the electron provides the necessary centripetal force for circular motion. Using CGS units (as indicated by the options), we have: mv^2 r = e^2 r^2 Multiplying both sides by r , we get: mv^2 = e^2 r The kinetic energy of the electron is given by: K = 1 2 mv^2 Substituting the value of mv^2 , we obtain: K = e^2 2r Answer: e^2 2r