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Electrostatics. Electrostatics: the study of charges at rest. AKA static electricity. 2 types of charge: + and – In the majority of cases, only the negative charges are mobile. Neutral : equal amnts of + and – charge. No net electric force. Electric Force. Non-contact force
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Electrostatics: the study of charges at rest. • AKA static electricity
2 types of charge: + and – • In the majority of cases, only the negative charges are mobile. • Neutral: equal amnts of + and – charge. No net electric force.
Electric Force • Non-contact force • Opposite charges attract, like charges repel.
Attractive forces lead one to conclude that at least one object is charged. • Repulsive forces provide convincing evidence that both objects must be charged.
Polarization: the process of separating opposite charges in an object. (Creating poles)
Law of Conservation of Charge • The total charge (difference between + and – charge) within an isolated system is always constant. • Charge can’t magically appear or disappear.
Charging by friction • Ex: shuffling across the carpet in socks. • Outer electrons are the least strongly bound and most easily shed. • Different materials have different affinities (desire, love) for electrons. • When in contact, one material may give up some of its electrons to the other. • Depends on the materials.
Insulators: hold on to outer e- • Conductors: weak hold on outer e-. Allow charges to flow freely
Charging by Conduction • Involves touching a charged object to a neutral object, thereby transferring some charge. • Charge will spread out uniformly onto the second object.
A + charged object brought into contact with something neutral will take e- away from that object, leaving both as a + charge. • Only e- are transferred.
Charging by Induction • A method used to charge an object without actually touching it to any charged object.
Ground: a large object that serves as an infinite source of e- or an e- sink. • Usually the Earth. • Grounding something allows excess charge to flow into the Earth.