Select the correct statements :

            I) The kinetic energy of charged particle moving in a uniform magnetic field does not change

            II) The direction of force act on the particle always perpendicular to the plane of the

            displacement of the particle so work done is zero.

            III) The frequency of charge circulating in cyclotron depend upon the speed of the charge

            IV) The time which charge spends inside a dee is independent of its velocity and radius of the

            semicircular path