A dielectric inserted between the plates of a charged, isolated capacitor causes the potential difference to
Correct answer: B. decrease, because the capacitance rises while the charge is fixed
- A. increase
- B. decrease, because the capacitance rises while the charge is fixed
- C. stay the same
- D. become zero
Explanation
With the capacitor disconnected the charge cannot change, and since V equals Q over C, raising the capacitance must lower the voltage. The dielectric molecules polarise and set up a field opposing the original one, which is the physical reason for the drop. If instead the capacitor stayed connected to a battery, the voltage would be fixed and the charge would rise.
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About Capacitors
Capacitors store electric charge and energy in an electric field between conductors. Work includes capacitance, the relation Q = CV, dielectric materials, charging and discharging, energy formulas, and combinations of capacitors in series and parallel. Electric potential difference is needed to understand why charge and stored energy change.
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