Question

An electric dipole consists of two equal but unlike charges separated by a distance. Two point charges, q1 = +4.5 x 10-6 C and q2 = -4.5 x 10-6 C, are separated by 6.4 x 10-2 m, forming an electric dipole as shown in the figure. Find the electric field halfway between the dipole.

Answer 1

Electric dipole

$P=2qd$

$$P=4.5\times10^{-6}\times6.4\times10^{-2}=2.88\times10^{-7}C \times m$$

Electric field at x-axis due to dipole

$E=\frac{2kP}{r^3}$

$$E=\frac{2\times9\times10^9\times2.88\times10^{-7}}{(3.2\times10^{-2})^3}=1.58\times10^8N/C$$