An electric dipole placed in a uniform electric field experiences
- A. a net force but no torque
- B. a torque but no net force
- C. neither force nor torque
- D. both a large net force and a torque
Explanation
The equal and opposite charges feel equal and opposite forces in a uniform field, so the forces cancel, but because they act along different lines they form a couple that turns the dipole into alignment with the field. In a non uniform field the two forces differ in size and a net force does appear. This turning effect is how polar molecules align in a dielectric.