PHYS1322-CH22Lec3

# PHYS1322-CH22Lec3 - Lecture 6 Quiz Thursday and Friday...

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Lecture 6 a b c s S E dS Φ≡ G G v Quiz, Thursday and Friday ± Group quiz Thursday ¾ 1 problem done in your group ± Individual quiz Friday ¾ 2 problems plus 5 multiple choice ± Problems on chapters 21-22 ± You may bring in one side of paper with notes ² Per group in the group quiz ² Per person in the individual •Field lines are a way of representing an electric field •Lines leave (+) charges and return to (-) charges •Number of lines leaving/entering charge charge •Tangent of line = direction of E •Local density of field lines local magnitude of E •Lines from an isolated charge go to infinity •Field lines cannot cross Last Week Rules for Field Lines + - Electric Dipole: Field Lines Consider imaginary spheres centered on : All lines leave a) All lines enter b) Equal amounts of leaving and entering lines for c) a a) + q (blue) b b) - q (red) c c) midpoint (yellow) Question 1 Examine the electric field lines produced by the charges in this figure. Which statement is true? (a) q 1 and q 2 have the same sign (b) q 1 and q 2 have the opposite signs and q 1 > q 2 (c) q 1 and q 2 have the opposite signs and q 1 < q 2 q 1 q 2 Field lines start from q 2 and terminate on q 1 . This means q 2 is positive; q 1 is negative; so, … not (a) Now, which one is bigger? Note that more field lines emerge from q 2 than end on q 1 This indicates that q 2 is greater than q 1 Electric Fields from Continuous Charge Distributions Principles (Coulomb’s Law + Law of Superposition) remain the same. Only change: Examples: line of charge charged plates electron cloud in atoms, … ++++++++++++++++++++++++++ r E(r) = ? Σ→

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Lecture 6 Charge Densities How do we represent the charge “ Q ” on an extended object?
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## This note was uploaded on 04/14/2008 for the course PHYS 1322 taught by Professor Ndili during the Fall '07 term at University of Houston.

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PHYS1322-CH22Lec3 - Lecture 6 Quiz Thursday and Friday...

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