Two positive ions having the same charge q but different masses m1 and m2 are accelerated horizontally from rest through a potential difference V. They then enter a region where there is a uniform magnetic field B normal to the plane of the trajectory.
(a) Show that if the beam entered the magnetic field along the x-axis, the value of the y-coordinate for each ion at any time t is approximately

Provided y remains much smaller than x.
(b) Can this arrangement be used for isotope separation? Why or why not?

y = Bx 8mV