Electric Dipole
A system of two equal and opposite electric charges (+q and -q) separated by a small distance d.
Governing formula
p = q d, V = (1 / (4π ε₀)) (p cos θ / r²)
SI unit
C·m (Coulomb-meters)
In depth
An electric dipole experiences zero net force in a uniform electric field, but experiences a net torque τ = p × E that acts to align the dipole vector with the external field.
Examples in the real world
Water molecules (H₂O) possessing permanent electric dipoles due to asymmetric polar covalent oxygen-hydrogen bonds.