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SECTION 25.3 • Electric Potential and Potential Energy Due to Point Charges 769 Figure 25.8 shows a plot of the electric potential on the vertical axis for a positive charge located in the xy plane. Consider the following analogy to gravitational poten- We obtain the electric potential resulting from two or more point charges by apply- ing the superposition principle. That is, the total electric potential at some point P due (25.12) where the potential is again taken to be zero at infinity and r i is the distance from the point P to the charge q i . Note that the sum in Equation 25.12 is an algebraic sum of scalars rather than a vector sum (which we use to calculate the electric field of a group E. The electric potential around a dipole is illustrated in Figure 25.9. Notice the steep slope of the V # k e
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q i r i y x 2 1 0 Electric potential (V) Figure 25.8 The electric potential in the plane around a single positive charge is plotted on the vertical axis. (The electric potential function for a negative charge would look like a hole instead of a hill.) The red line shows the 1/r nature of the electric potential, as given by Equation 25.11. 2 1 0 –1 –2 Electric potential (V) Figure 25.9 The electric potential in the plane containing a dipole. Electric potential due to several point charges |