For any given quadrupole, let the charges be +q, −q, +q, and −q at the corners of the square, and l be the side of the square. Calculate approximately the electric potential and the electric field far away from the quadrupole, IN THE THREE-DIMENSIONAL SPACE. You will verify that φ decays like 1/r^3 and E decays like 1/r^4 at large r, where r is the distance between the point of interest and the center of the square. Assume that r l.

Question

For any given quadrupole, let the charges be +q, −q, +q, and −q at the corners of the square, and l be the side of the square. Calculate approximately the electric potential and the electric field far away from the quadrupole, IN THE THREE-DIMENSIONAL SPACE. You will verify that φ decays like 1/r^3 and E decays like 1/r^4 at large r, where r is the distance between the point of interest and the center of the square. Assume that r >> l.