📌 Derivation:

Setup:
• Dipole: charges +q and −q, separated by distance 2a (dipole length).
• Dipole moment: <b>p = q × 2a</b>
• Point P is on the <b>axial line</b> at distance r from centre.

Step 1 — Distance from each charge to P:
r₁ = r − a (from +q)
r₂ = r + a (from −q)

Step 2 — Potential at P:
V = k[+q/r₁ + (−q)/r₂]
V = kq [1/(r−a) − 1/(r+a)]
V = kq [(r+a − r+a) / (r²−a²)]
V = kq [2a / (r²−a²)]

Step 3 — In terms of Dipole Moment (p = 2qa):
V = kp / (r² − a²)

Step 4 — For Short Dipole (r &gt;&gt; a, so a² &lt;&lt; r²):
┌──────────────────┐
│ V = kp / r² │
└──────────────────┘

Note: At <b>equatorial point</b>, V = 0 (positive and negative contributions cancel).