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title: "An isolated, charged parallel-plate capacitor has a uniform electric field between its plates. A dielectric slab composed of polar molecules is inserted into the space between the plates, resulting in a reduced net electric field inside the dielectric. Which of the following best explains the microscopic mechanism responsible for this reduction in electric field and distinguishes it from the behavior of a conductor?"
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url: "https://nerd-notes.com/ubq/118189/"
date_modified: "2026-08-04T08:07:58+00:00"
---

# An isolated, charged parallel-plate capacitor has a uniform electric field between its plates. A dielectric slab composed of polar molecules is inserted into the space between the plates, resulting in a reduced net electric field inside the dielectric. Which of the following best explains the microscopic mechanism responsible for this reduction in electric field and distinguishes it from the behavior of a conductor?

An isolated, charged parallel-plate capacitor has a uniform electric field between its plates. A dielectric slab composed of polar molecules is inserted into the space between the plates, resulting in a reduced net electric field inside the dielectric. Which of the following best explains the microscopic mechanism responsible for this reduction in electric field and distinguishes it from the behavior of a conductor?

- **A.** Free electrons in the dielectric migrate to the surface of the slab, completely neutralizing the external field, whereas in a conductor, molecules merely rotate without charge migration.
- **B.** The external field exerts torques that align the molecular dipoles with their positive ends pointing toward the positively charged plate, increasing the net field inside the dielectric.
- **C.** The external field exerts torques that reorient the molecular dipoles, producing bound surface charges that create an induced field opposing the external field, whereas in a conductor, free electrons move across the material.
- **D.** Thermal agitation ionizes the polar molecules, producing mobile ions that flow to the dielectric boundaries, whereas in a conductor, bound charges stretch without moving.

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