7.3 Exercise 16

Two charges $–2.0 \mu \text{C} \text{and} + 2.0 \mu \text{C}$ are separated by 4.0 cm on the z-axis symmetrically about origin, with the positive one uppermost. Two space points of interest $P_{1} \text{and} P_{2}$ are located 3.0 cm and 30 cm from origin at an angle $30 °$ with respect to the z-axis. Evaluate electric potentials at $P_{1} \text{and} P_{2}$ in two ways: (a) Using the exact formula for point charges, and (b) using the approximate dipole potential formula.