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Unformatted text preview: Physics 122 Spring 2009 – Document #05: Cycle 1 Review Sheet page 1 of 14 PHYS 122: Cycle 1 Review Sheet January 14, 2009 SLIGHTLY UPDATED January 30, 2009 This “Review Sheet” delineates all main topics that students will be responsible for for the First Hour Exam which will take place Friday, February 6 at 9:30 AM. What is the points of this course? During the first two lectures we argued that an understanding of electrical and magnetic phe- nomena is a critical component to the development and application of an enormous range of devices in medical technology, communications, computing, media presentation, etc., etc., all of which are defining components of life in our modern society. I argued that a proper technical understand- ing and application of these devices require an understanding of the physics behind them and the methods of data interpretation that are characteristic of the physical sciences. I also argued that in medical technology, as well as in many other fields, we are required to deal with a wide range of electronic, electrical, and electro-magnetic devices. To fully understand how these devices work, their strengths and limitations, we require a basic and fundamental understanding of the physical laws of the universe that govern the interactions in electricity and magnetism. What is the electrostatics and what is the point of it? In order to understand the function and application of any electric or electro-magnetic device, we must start with the most fundamental electric interaction and the concept of electric charge. Everything is built upon this. The sub-discipline of electrostatics means the physics of systems where the charges in the system are not moving. We began with Coulomb’s law which tells us how two simple point charges interact. We showed how Coulomb’s Law can be applied to a system of several point charges. We introduced the concept of the Electric Field which allows us to specify the electric force (per unit test charge) at any point in space due to a configuration of point charges. We also introduced the concept of the Electric Potential (i.e. “voltage”) that provides a means of describing the potential energy (per unit test charge) due to the electric field. Next, we introduced the concept of electric current – the motion of charge that is constrained along some path (like a wire). All of this sets the stage for dealing with our first application of electrostatics: simple circuits. The Concept of Charge: The idea of charge is both familiar and mysterious. Everything we do in this course is based on the property called charge. One important idea to keep in mind: In most materials, which are made of atoms, there are equal numbers of positive and negative “charged particles” (namely protons and electrons). In real macroscopic objects that have a non-zero electric charge (be it positive or negative), this charge is based on the small difference between the number of electrons and the number of protons in the object. In a negatively charged object, there is a small excessand the number of protons in the object....
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This note was uploaded on 11/06/2009 for the course PHYS 122 taught by Professor Raman during the Spring '09 term at Lehigh University .
- Spring '09