A. A singly charged ion of unknown mass moves in a circle of radius 13.0 cm in a magnetic field of 1.1 T. The ion was accelerated through a potential difference of 8.0 kV before it entered the magnetic field. What is the mass of the ion? in kg
B. Crossed electric and magnetic fields are established over a certain region. The magnetic field is 0.655 T vertically downward. The electric field is 3.22x10^6 V/m horizontally east. An electron, traveling horizontally northward, experiences zero net force from these fields and so continues moving in a straight line. What is the electron's speed? in m/s