Question

An electric dipole of dipole moment 6×10⁻⁶ C·m is kept in a uniform electric field of 10N/C such that the dipole moment and the electric field are parallel. Calculate the potential energy of the dipole.

a. 3×10⁻⁵ J
b. 6×10⁻⁵ J
c. 9×10⁻⁵ J
d. 12×10⁻⁵ J

Answer 1

The potential energy of an electric dipole of dipole moment 6×10⁻⁶ C⋅m in a uniform electric field of 10 N/C, with the dipole moment and electric field parallel, is 6×10⁻⁵ J. The correct answer is option b.

Step-by-step explanation:

To calculate the potential energy of the electric dipole in a uniform electric field, we can use the formula

U = -μ ⋅ E,

where U is the potential energy, μ is the dipole moment, and E is the electric field strength. Since the dipole moment and the electric field are parallel, the cosine of the angle between them (θ) is 1.

Using the given dipole moment (6×10⁻⁶ C⋅m) and electric field (10 N/C), we get:

U = -(6×10⁻⁶ C⋅m) ⋅ (10 N/C) ⋅ cos(0°)

U = -6×10⁻⁵ J

Because potential energy is the capacity for doing work, which is considered as a scalar quantity, it can be expressed positively. Thus, the potential energy of the dipole is 6×10⁻⁵ J, which corresponds to option (b).