5. Atomic Mass Spectroscopy. Figure 7: A velocity selector (left) and a mass spectrometer (right). (a) Velocity selector: The electric field between two conducting plates, E = - Fk, points vertically downwards as shown in the figure. The magnetic field between the plates, B = Bj is into the page. A charge enters the region between the plates moving right at a velocity v =i, (1) Determine the force on the particle. (ii) At what speed should the particle be injected in order that it undergoes no deflection in passing between the plates? Give your answer in terms of , &' and B. *(iii) Particles that are deflected get stuck to the plates. Thus this device functions as a velocity selector. Only particles that travel at the speed calculated in part (ii) emerge from between the plates. (b) Mass spectrometer: To the right of the screen shown in the figure, a uniform magnetic field B points directly into the page. A particle of mass m and charge moving at a speed v enters this region through a hole in the screen. (i) Describe the subsequent motion of the particle (one or two sentences). (ii) At what distance h should the detector D be placed to ensure that it captures the deflected particle? Give your answer in terms of , B,m and v