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23 Electric Fields. Suppose we fix a positive charge q 1 in place and then put a second positive point charge q 2 near it. Since the charges do not touch, how can q 1 exert a force on q 2 ?. 23-1 Charges and Forces:A Close Look. The question about action at a distance
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23 Electric Fields Suppose we fix a positive charge q1 in place and then put a second positive point charge q2 near it. Since the charges do not touch, how can q1 exert a force on q2?
23-1 Charges and Forces:A Close Look The question about action at a distance can be answered by saying that q1 sets up an electric field in the space surrounding it.
23-2 The Electric field Definition of Electric Field
23-3 Electric Field Lines Field lines originate on positive charges and terminate on negative charges.
field lines for a positive and a negative point charge that are equal in magnitude
If we place a positive test charge q0 near n point charges q1,q2 ,…,qn,then,from Eq.22-7,the net force from the n point Charges acting on the test charge is
Step two: Step three:
Step one: Step two: Step three: Step four:
Step five: Step six:
If we let R→∞ while keeping z finite: This is the electric field produced by an infinite sheet of uniform charge located on one side of a nonconductor such as plastic.
Field Due to a Continuous Charge Distribution The electric field due to a continuous charge distribution is found by treating charge elements as point charges and then summing,via integration the electric field vectors produced by all the charge elements.
23-8 A Point Charge in an Electric Field The electrostatic force acting on a charged particle located in an external electric field has the direction of if the charge q of the particle is positive and has the opposite direction if q is negative.
Sample problem 23-4 Step one: Step two: Step three:
Sample problem 23-5 (a) Step one: Step two:
(b) (c) 主菜单