Which statements must be true about the surface of a charged conductor in which no charge is moving? 1. The electric potential is constant over the surface.
2. The electric field is constant at the surface.
3. The electric field is zero at the surface.
4. The electric field is perpendicular to the surface.
5. The electric potential of the surface is zero.

Acyclotron is used to produce a beam of high-energy deuterons that then collide with a target to produce radioactive isotopes for a medical procedure. deuterons are nuclei of deuterium, an isotope of hydrogen, consisting of one neutron and one proton, with total mass 3.34×10−27kg. the deuterons exit the cyclotron with a kinetic energy of 6.40 mev .a-what is the speed of the deuterons when they exit? b-if the magnetic field inside the cyclotron is 1.25 t, what is the diameter of the deuterons' largest orbit, just before they exit? c-if the beam current is 350 μa how many deuterons strike the target each second?