Q. Two large, parallel, conducting plates are 21cm apart and have charges of equal magnitude and opposite sign on their facing surfaces. An electrostatic force of 4.1 x10-15 N acts on an electron placed anywhere between the two plates.
Q. Two pieces of plastic, a full ring and a half ring, have the similar radius and charge density (charge per length). Which electric field at the center has greater magnitude? Defend the answer.