Jump to a New ChapterIntroduction to the SAT IIIntroduction to SAT II PhysicsStrategies for Taking SAT II PhysicsVectorsKinematicsDynamicsWork, Energy, and PowerSpecial Problems in MechanicsLinear MomentumRotational MotionCircular Motion and GravitationThermal PhysicsElectric Forces, Fields, and PotentialDC CircuitsMagnetismElectromagnetic InductionWavesOpticsModern PhysicsPhysics GlossaryPractice Tests Are Your Best Friends
 13.1 Electric Charge 13.2 Electric Force 13.3 Electric Field 13.4 Electric Potential

 13.5 Conductors and Insulators 13.6 Key Formulas 13.7 Practice Questions 13.8 Explanations
Conductors and Insulators
Idealized point charges and constant electric fields may be exciting, but, you may ask, what about the real world? Well, in some materials, such as copper, platinum, and most other metals, the electrons are only loosely bound to the nucleus and are quite free to flow, while in others, such as wood and rubber, the electrons are quite tightly bound to the nucleus and cannot flow. We call the first sort of materials conductors and the second insulators. The behavior of materials in between these extremes, called semiconductors, is more complicated. Such materials, like silicon and germanium, are the basis of all computer chips.
In a conductor, vast numbers of electrons can flow freely. If a number of electrons are transmitted to a conductor, they will quickly distribute themselves across the conductor so that the forces between them cancel each other out. As a result, the electric field within a conductor will be zero. For instance, in the case of a metal sphere, electrons will distribute themselves evenly so that there is a charge on the surface of the sphere, not within the sphere.
 Jump to a New ChapterIntroduction to the SAT IIIntroduction to SAT II PhysicsStrategies for Taking SAT II PhysicsVectorsKinematicsDynamicsWork, Energy, and PowerSpecial Problems in MechanicsLinear MomentumRotational MotionCircular Motion and GravitationThermal PhysicsElectric Forces, Fields, and PotentialDC CircuitsMagnetismElectromagnetic InductionWavesOpticsModern PhysicsPhysics GlossaryPractice Tests Are Your Best Friends
Test Prep Centers
SparkCollege
 College Admissions Financial Aid College Life