Adding a dielectric to a capacitor
A dielectric is inserted between the plates of a capacitor that stays connected to a battery. What happens?
Answer B: explanation for every choice
A
A dielectric increases capacitance.
B
Correct. A dielectric raises C by a factor κ. With V fixed by the battery, Q = CV increases.
C
While connected, the battery holds the voltage constant.
D
Charge stays constant only if the capacitor is disconnected first.
TakeawayC = κε₀A/d. Connected to a battery, V is fixed, so Q rises with C.
Equation usedCapacitance and stored energy
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