Question

If this dipole is kept in a uniform external electric field E₀, diagrammatically represent the position of the dipole in stable and unstable equilibrium and write the expressions for the torque acting on the dipole in both the cases.

Answer 1

When the dipole were kept in a uniform electric field E₀. The torque acting on dipole,

τ = p × E = pE sinθ

(a) If θ = 0°,then τ = 0, p||E

(b) If θ = 180°, then τ = 0, p||-E