1. Copyright © 2009 Pearson Education, Inc. © 2009 Pearson Education, Inc. This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students except by instructors using the accompanying text in their classes. All recipients of this work are expected to abide by these restrictions and to honor the intended pedagogical purposes and the needs of other instructors who rely on these materials. Physics for Scientists and Engineers, with Modern Physics, 4th edition Giancoli Unit 1 Electrostatics

2. Day 1 Electric Charge

3. Static Electricity; Electric Charge and Its Conservation Electric Charge in the Atom Insulators and Conductors Objectives

4. The Elementary Electric Charge is called e Like charges repel, unlike charges attract Charges come in two types: (+e) & (- e) where e = 1.602 x 10 -19 Coulombs `

5. Objects can be charged by rubbing (ie: rubber rod becomes negative when rubbed with rabbit pelt, glass rod becomes positive when rubbed with silk )

6. Charge Carriers The primary charge carrier is the electron An object has a net negative charge if it is given excess electrons An object has a net positive charge if it has an electron debt.

7. Objects are considered to be electrically neutral if the object has the same number of (+) charges as (-) charges A neutral atom has the same number of electrons as protons A neutral atom is said to be ionized if one or more of its valence electrons is added or removed Electric charge cannot be created or destroyed. This is called Conservation of electric charge

8. Some molecules are said to be Polarized if the charges of the constituent atoms are not uniformly distributed. A Polar Molecule is overall electrically neutral

9. Insulators & Conductors Materials that inhibit the flow of electric charge over its surface are called an electrical insulator ie: wood, plastic (PVC), glass, rubber Materials that permit the flow of electric charge over its surface are called electrical conductors ie: Metals such as Gold, Silver, Copper, Aluminum Materials which can exhibit intermediate amounts of electrical conductivity are called semi-conductors ie: Silicon, Germanium, Gallium Arsenide

10. Conductor: Charge flows freely Metals Insulator: Almost no charge flows Most other materials