Electric Potential Energy of Charge Systems · PhysicsBowl 2007 #28
Physics · electromagnetism
Problem
Which statement about a system of point charges that are fixed in space is necessarily true?
(a) If the potential energy of the system is negative, net positive work by an external agent is required to take the charges in the system back to infinity.
(b) If the potential energy of the system is positive, net positive work is required to bring any new charge not part of the system in from infinity to its final resting location.
(c) If the potential energy of the system is zero, no negative charges are in the configuration.
(d) If the potential energy of the system is negative, net positive work by an external agent was required to assemble the system of charges.
(e) If the potential energy of the system is zero, then there is no electric force anywhere in space on any other charged particle not part of the system.