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.