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Placing a dielectric between the plates of a capacitor increases the energy of the capacitor.

a) True.

b) False.

User Janki
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1 Answer

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Final answer:

Placing a dielectric between the plates of a capacitor does not increase energy; it reduces the electric field and voltage, thereby increasing capacitance but decreasing the stored energy.

Step-by-step explanation:

The statement that placing a dielectric between the plates of a capacitor increases the energy of the capacitor is false. When a dielectric material is inserted into a capacitor, the electric field within the capacitor is reduced. This happens because the molecules in the dielectric material become polarized, creating a layer of opposite charge that reduces the field's strength. As a result, the voltage across the plates decreases for the same amount of charge, which effectively increases the capacitance of the capacitor because capacitance is defined as C = Q/V (charge over voltage). However, the energy stored in the capacitor, given by ½CV^2, actually decreases because the voltage V is reduced while the charge Q remains the same. The energy effectively goes into polarizing the dielectric material, which can be thought of as stretching microscopic springs within the material.

User Mike Resoli
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