Question

Calculate electric field due a electric dipole along axial and equatorial line

Answer 1

By using the formula for electric field due to point charge,

Electric field due to +q = +1/4πε0 q/(r - l)2

The distance between (P and +q) = (r-l)

Electric field due to -q = -1/4πε0 q/(r + l)2

E = E1 + E2 (Vector addition)

E = q.4rl/4πε0(r2 - l2)2

Since dipole is very small, we neglect the higher power values

E = 2P/4πε0r2