17.43. Set Up: For a point charge, is toward a negative charge and away from a positive charge. Let and For the net electric field to be zero, and must have equal magnitudes and opposite directions. Figure 17.43 Solve: The two charges and the directions of their electric fields in three regions are shown in Figure 17.43a. Only in region II are the two electric fields in opposite directions. Consider a point a distance x from so a distance from gives and is the positive solution. The electric field is zero at a point between the two charges, 0.24 m from the 0.500 nC charge. (b) Let be the negative charge. The two charges and the directions of their electric fields in three regions are shown in Figure 17.43b. and are in opposite directions in regions I and III. But for the magni-tudes of the fields to be equal the point must be closer to the charge that has smaller magnitude, and that occurs only for region I. Consider a point a distance x to the left of so from gives and is the positive solu-
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This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.