Electric Dipole
o
The vector associated with every area element of a closed surface is taken to be in the direction of the outward normal .
o Area element vector ΔS = ΔS nn , ΔS is magnitude of area element and nnis unit vectorin the direction of outward normal .
o Electric flux , Δφ = EΔS = E ΔScosθ , θ is angle between E and ΔS . o Unit of electric flux is NC -1 m 2 . o
Total flux through a surface , φ ≈ Σ EΔS
Electric Dipole
An electric dipole is a pair of equal and opposite point charges q and – q , separated by a distance of 2a .
o Direction from – q to q is the direction of the dipole . o
The mid-point of locations of – q and q is called the center of the dipole .