6. The diagram below shows the electric and magnetic fields in a device called a velocity selector. This device is used to ensure that the ions (or electrons) of an ion beam are all moving at the desired speed tselect- The beam is sent into a region of strong electric field E = Eoâý and magnetic field B = Boê which causes the beam to spread based on the speed of the ions in the beam. These fields are set so that the ions moving at a particular speed vselect move in a straight line without any net force acting on them. The black screen immediately following the region blocks all of the ions except those moving at the desired speed. Region with E & B fields Incoming lon beam with a range of speeds lons with speed v_select (a) Supposing that the ions have a positive charge, analyze the motion of an ion in the region with E and B fields using Newton's 2nd Law. (b) Write an expression for the speed viselect for which the particle's momentum is unaffected.

6. The diagram below shows the electric and magnetic fields in a device called a velocity selector. This device is used to ensure that the ions (or electrons) of an ion beam are all moving at the desired speed tselect- The beam is sent into a region of strong electric field E = Eoâý and magnetic field B = Boê which causes the beam to spread based on the speed of the ions in the beam. These fields are set so that the ions moving at a particular speed vselect move in a straight line without any net force acting on them. The black screen immediately following the region blocks all of the ions except those moving at the desired speed. Region with E & B fields Incoming lon beam with a range of speeds lons with speed v_select (a) Supposing that the ions have a positive charge, analyze the motion of an ion in the region with E and B fields using Newton's 2nd Law. (b) Write an expression for the speed viselect for which the particle's momentum is unaffected.