An electric dipole of moment Vector p is placed in a uniform electric field Vector E, With Vector p parallel to Vector E. It is then rotated by an angle θ. The work done is
(a) pEsin θ
(b) pEcos θ
(c) pE(1 - cos θ)
(d) pE(1 - sin θ)
Correct Answer is: (c) pE(1 - cos θ)
τ = pEsin θ.
Work = ∫τ dθ = ∫0θ pEsin θ = pE [cos θ]θ0
= pE(1 - cos θ).
