PHYSICS 200 CLASS 1 SPRING 2004 ASSIGNMENT - Employees ...

3. Hint on problem 23Note that you already have the potential of a point charge (derived in class) and thepotential for a dipole (Equation 25-30, which I haven't derived, but which I trust all ofyou will do—it would make a good exam question). Since the potentials are scalars,one can just add them.In the coordinate system chosen by the problem, the algebra is simplest if you choosethe middle charge as the point charge, and the other two as the dipole. If you makethis choice, NOTE THAT THE DEFINITION OF d IS DIFFERENT FROM THATOF EQ 25-30. You must make the appropriate transformation.One gets the same result if you choose the two bottom charges as the dipole, but thealgebra is a little more involved.