Electricity and Magnetism Chapter 7 Overview Electricity Charge
- Slides: 9
Electricity and Magnetism Chapter 7 Overview
Electricity Charge of proton Positive n Charge of electron Negative n Charge of neutron NONE n Atoms have no charge because the charges of the protons and electrons cancel each other out. n Atoms become charged by gaining or losing electrons n
Electricity n Why you end up with a static shock after walking across the carpet: n n Atoms in the carpet hold their electrons more loosely than atoms in your shoes Shoes gain electrons from the carpet, becoming negatively charged Carpet loses electrons & becomes positively charged Shock occurs when electrons are suddenly transferred from one object to another- this appears as a spark
Electroscope Used to detect static electricity n Electrons are transferred to the metal ball and down to the foil n Foil becomes negative and repels n
Static Electricity n Static electricity- buildup of excess negative charge on an object Excess electrons on an object n Very short electric discharge n Law of conservation of charge- charge may be transferred from object to object, but it cannot be created or destroyed n Opposite Charges attract, and like charge repel n
Electricity Charges can act on each other even at a distance because any charge that is placed in an electrric field will be pushed or pulled by the field n Electrons move more easily through conductors, like metals n Metals conduct well because: atoms in metals have electrons that move easily through the material n http: //www. eng. auburn. edu/~wfgale/intro_metals/s ection 1. htm n
Electricity n Insulator- a material that doesn’t allow electrons to move through it easily n Occurs because electrons are held tightly to the atoms in insulating materials – like wood, plastic, glass Charging by contact- the process of transferring charge by touching or rubbing two objects together n Charging by induction- rearrangement of electrons on a neutral object by a nearby charged object n
n Charging by Induction http: //regentsprep. org/Regents/physics/phys 03/aeleclab/induct. htm
Electricity Grounding- using a conductor to direct an electric charge into the ground n The presence of electric charges can be detected by an electroscope. n