E & M UNIT 01 - Electric Charge Charge and Coulombâ€™s Law A) Students should understand the concept of electric charge, so they can: (1) Describe the types of charge and the attraction and repulsion of charges. (2) Describe polarization and induced charges. B) Students should understand Coulombâ€™s Law and the principle of superposition, so they can: (1) Calculate the magnitude and direction of the force on a positive or negative charge due to other specified point charges. (2) Analyze the motion of a particle of specified charge and mass under the influence of an electrostatic force. ELECTROSTATICS AND CONDUCTORS (A) Students should understand the nature of electric fields in and around conductors, so they can: (1) Explain the mechanics responsible for the absence of electric field inside a conductor, and know that all excess charge must reside on the surface of the conductor. (2) Explain why a conductor must be an equipotential, and apply this principle in analyzing what happens when conductors are connected by wires. (3) Show that all excess charge on a conductor must reside on its surface and that the field outside the conductor must be perpendicular to the surface. (B) Students should be able to describe and sketch a graph of the electric field and potential inside and outside a charged conducting sphere. (C) Students should understand induced charge and electrostatic shielding, so they can: (1) Describe the process of charging by induction. (2) Explain why a neutral conductor is attracted to a charged object. (3) Explain why there can be no electric field in a charge-free region completely surrounded by a single conductor, and recognize consequences of this result. (4) Explain why the electric field outside a closed conducting surface cannot depend on the precise location of charge in the space enclosed by the conductor, and identify consequences of this result.