Field Lines — Dipole
Streamlines from + to −. Adjustable separation. Animated dots travel along lines.
Key Notes
Dipole = +q and −q separated by small distance d. Dipole moment p⃗ = qd⃗ (from − to +).
Field lines emerge from + and curve to enter −. Density highest along the dipole axis.
Far away, |E| ∝ 1/r³ — falls faster than a single point charge (which goes as 1/r²).
Net charge of dipole = 0, but E ≠ 0 because charges aren't at the same point.
Formulas
Dipole moment
Vector from −q to +q, magnitude qd.
Axial field
On the axis, far from dipole.
Equatorial field
Antiparallel to p⃗ on equatorial plane.
Important Points
Axial field is twice the equatorial field at the same distance.
On the equatorial line, E is opposite to p⃗.
For r ≫ d (short dipole), expressions are exact in the limit d → 0 with p fixed.
Field Lines — Dipole notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 12 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.