An electric dipole consisting of charges of magnitude 2.00 nC separated by 8.40 μm is in an electric field of strength 1390 N/C. What are (a) the magnitude of the electric dipole moment and (b) the difference between the potential energies for dipole orientations parallel and antiparallel to E→ ?

(a) The magnitude of the electric dipole moment is 1.68 x 10⁻¹⁴ C.m

(b) The difference between the potential energies ΔU, is 4.6704 x 10⁻¹¹ J

Explanation:

Given;

magnitude of charge, q = 2 nC = 2 x 10⁻⁹ C

distance of separation, d = 8.4 μm = 8.4 x 10⁻⁶ m

strength of electric field, E = 1390 N/C

(a) the magnitude of the electric dipole moment

p = qd

p = (2 x 10⁻⁹ C)(8.4 x 10⁻⁶ m)

p = 1.68 x 10⁻¹⁴ C.m

(b) the difference between the potential energies for dipole orientations parallel and anti-parallel to E

ΔU = U(180) - U(0)

ΔU = 2pE

ΔU = 2(1.68 x 10⁻¹⁴ )(1390)

ΔU = 4.6704 x 10⁻¹¹ J