An electron \left(mass = 9.1\times 10^{-31}kg; Charge=-1.6\times 10^{-19}C \right) experiences no deflection if subjected to an electric field of \[3.2\times 10^{5} V/m\] and a magnetic field of 2.0 × 10-³ Wb/m² . Both the fields are normal to the path of electron and to each other . If the electric field is removed, then the electron will revolve in an orbit of radius:

A charged particle of mass m, charge q is moving with speed v. It enters a uniform magnetic field acting perpendicular to the plane of paper inwards as shown in Fig. The width of the
magnetic field is √3 mv/2qB . Then time taken by charged particle to emerge from the magnetic
field is :