Electric fields

# Electric fields - Force Fields In physics, a force field is...

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Force Fields In physics, a force field is a way to picture the effects that electric charges have on one another. Instead of talking about the force a positive (+) charge exerts on an electron, we can say the charge creates a force "field" in the empty space around it. An electron put down at any place in this force field is pulled towards the + charge; a positive charge set down at the same place is pushed away. Field A field is an area that applies a push or a pull on some object. Physicists often represent fields with field diagrams where the field is represented by lines. Although very unrealistic it does give us a picture of what the field in that area might look like. The thing to realize is the field is actually in three dimensions surrounding the object without visible gaps Electrical Fields Electric field is defined as the electric force per unit charge. The direction of the field is taken to be the direction of the force it would exert on a positive test charge. The electric field is radially outward from a positive charge and radially in toward a negative point charge The concept of the electric field was introduced by Michael Faraday. The electrical field force acts between two charges, in the same way that the gravitational field force acts between two masses. Electric Fields are an electric property associated with each point in space when charge is present in any form. The magnitude and direction of the electric field are expressed by the value of E , called electric field strength or electric field intensity or simply the electric field. Knowledge of the value of the electric field at a point, without any specific knowledge of what produced the field, is all that is needed to determine what will happen to electric charges close to that particular point By convention, Physicists chose that the electric field would come out of a positive charge and go into a negative charge. The direction is determined by which way the electric force would be on a positive test charge. Remember this is just a convention. The intensity of a field is represented by the density of the field lines. The more lines that are present in an area, the stronger the electric field would be in that area

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Intro Most audio equipment and computer towers are encased in metal boxes. Why do you think the metal is necessary? Can you believe that there is some connection between this question and the recent interest in the DNA mapping of the human genome? The common thread is electric force. To learn more about these applications, we must take a closer look at electric force. The electric force is an “action-at-a-distance” force, since electric charges attract or repel each other even when not in contact. According to Coulomb’s law, the magnitude of the force between two point charges is given by = Fe k q1q2r2 Electric forces are the attraction between objects or particles with electric charge. Electric force was described as a non-contact force. The electric force acts over the distance separating the two objects. Electric force is an action-at-
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## This note was uploaded on 05/15/2011 for the course ECON 103 taught by Professor Miyzaki during the Spring '11 term at Brown College.

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Electric fields - Force Fields In physics, a force field is...

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