A velocity selector consists of electric field E=Ek^ and magnetic field B=Bj^ with B=12 mT.
The value E required for an electron of energy 728 eV moving along the positive x-axis to pass undeflected is:
(Given, mass of electron =9.1×10−31 kg)
(A) 192 kVm −1
(B) 192 mVm −1
(C) 9600 kVm −1
(D) 16 kVm −1