An electic dipole of length 2cm is placed with its axis making an angle 60 degree with respect to a uniform electric field of 10⁵ N/C. If it experiences a torque of 13.856 Nm, calculate the- magnitude of the charge on the dipole & PE of the dipole.

The torque on an electric dipole placed in uniform electric field is given as

τ = qdE sinθ

or magnitude of charge will be

q = τ / dEsinθ

here

τ = 13.856 Nm

d = 2cm = 0.02m

E = 10⁵ N/C

θ = 60 degrees

so,

q  = 13.856 / (0.02 x 10⁵ x sin60)

thus,

q = 8 mC

now,

The potential energy of an electric dipole placed in uniform electric field is given as

U = pEcosθ = (q2d)Ecosθ

so,

U = 8x10^-3 x 2x0.02 x 10⁵ x cos60

thus,

U = 16 J