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- PHY102 Physics II © Dr.Cem Özdoğan
- 22-4 The Electric Field due to a Point Charge
- To find the electric field due to a point charge q (or charged particle) at any point at a distance r from the point charge, we put a positive test charge q0 at that point.
- The electric field vectors at various points around a positive point charge.
- Therefore, the net electric field at the position of the test charge is
- The direction of E is directly away from the point charge if q is positive, and directly toward the point charge if q is negative. The electric field vector is:
- The net, or resultant, electric field due to more than one point charge can be found by the superposition principle.
- If we place a positive test charge q0 near n point charges q1, q2, . . . , qn, then, the net force, F0, from the n point charges acting on the test charge is
- Getting smaller when away from