Lecture 1Electric ChargeChapter 22Electric Charge (1)• Electric charge is a fundamental property of atomic particles– such as electrons and protons• Two types of charge: negative and positive– Electron is negative, proton is positive• Usually object has equal amounts of each type of charge so no net charge• Object is said to be electrically neutralElectric Charge (2)• Object has a net charge if two types of charge are not in balance• Object is said to be charged• Net charge is always small compared to the total amount of positive and negative charge contained in an object• The net charge of an isolated system remains constantElectric Charge (3)• Charged objects interact by exerting forces on one another• Law of Charges:Like charges repel, and opposite charges attract• The standard unit of charge is the Coulomb (C)Electric Charge (4)• Electrical properties of materials such as metals, water, plastic, glass and the human body are due to the structure and electrical nature of atoms• Atoms consist of protons (+), electrons (-), and neutrons (electrically neutral)• Electrically neutral atoms contains equal numbers of protons and electronsElectric Charge (5)• Atoms combine to form solids • Sometimes outermost electrons move about the solid leaving positive ions • These mobile electrons are called conduction electrons• Solids where electrons move freely about are called conductors – metal, body, water• Solids where charge can’t move freely are called insulators – glass, plasticElectric Charge (6)• Only the conduction electrons can move• The positive ions are fixed in place• Electric charge transfer is a transfer of electrons• Charging positively: Removal of electrons from an object• Charging negatively: Addition of electrons to an
View Full Document
Unlocking...