(Solved): Electric quadrupole. The figure shows an electric quadrupole. It consists of two dipoles with dipo ...

Electric quadrupole. The figure shows an electric quadrupole. It consists of two dipoles with dipole moments that are equal in magnitude but opposite in direction. What is the value of \( E \) on the axis of the quadrupole for a point \( P \) a distance \( z \) from its center (assume \( z>>d \) )? Take \( Q=2 q d^{2} \) (which is known as the quadrupole moment of the charge distribution.)