Q. An ion source is producing 6Li ions, which have mass 9.99 x10-27 kg and charge +e. The ions are accelerated by a potential difference of 30 kV and pass horizontally into a region in which there is a uniform vertical magnetic field of magnitude B = 2.4 T. Calculate the strength of the smallest electric field, to be set up over the same region, that will allow the 6Li ions to pass through undeflected.