🧲 Electric Dipole — p in a uniform field: torque, energy, oscillation

Release the dipole away from alignment and it swings like a pendulum. The purple arc rotates with the dipole and shows which way the torque is turning it.

Walkthrough 1 / 5

Step 1 — the dipole alone, pinned at its centre on the grey axis.

Charge q 2.0 nC

Separation d 4.0

External field E 1.0

Start angle θ₀ 70°

Damping 0.10

θ = 70° · τ = 1.88 (arb)
p = 8.0 · U = -0.68 (arb)

τ is zero at θ = 0° and 180°
θ = 0° is STABLE · θ = 180° is not

Animation speed 1.0×