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Figure 18.18 shows two charged objects, A and B. Each contributes as follows to the net electric field at point P: EA =3.00 N/C directed to the right, and EB=2.00 N/C directed downward. Thus, EA and EB are perpendicular. What is the net electric field at P?
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The electric field contributions EA and EB, which come from the two charge distributions, are added vectorially to obtain the net field E at point P. |
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Reasoning
The net electric field E is the vector sum of EA and EB: E=EA+EB. As illustrated in Figure 18.18, EA and EB are perpendicular, so E is the diagonal of the rectangle shown in the drawing. Thus, we can use the Pythagorean theorem to find the magnitude of E and trigonometry to find the directional angle q .
Solution
The magnitude of the net electric field is
The direction of E is given by the angle q in the drawing:
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