A dipole with moment p = 4 × 10⁻¹⁰ C·m is aligned parallel to a uniform electric field of 2 × 10⁴ N/C. The potential energy of the dipole is:
Correct answer: A. -8 × 10⁻⁶ J
- A. -8 × 10⁻⁶ J
- B. 8 × 10⁻⁶ J
- C. Zero
- D. 4 × 10⁻⁶ J
Explanation
Potential energy of a dipole is U = -pE cosθ. For θ = 0° (parallel), cosθ = 1, so U = -pE = -(4 × 10⁻¹⁰)(2 × 10⁴) = -8 × 10⁻⁶ J.
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Electrostatics describes forces between charges through Coulomb's law, electric fields and field intensity, then uses electric potential to measure energy per unit charge. Capacitors store charge and electrical energy, with capacitance depending on geometry and dielectric material, not simply on the amount of charge present.
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