A bulb and a capacitor are connected in series across an ac supply. A dielectric is then placed between the plates of the capacitor. The glow of the bulb:
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Question

A bulb and a capacitor are connected in series across an ac supply. A dielectric is then placed between the plates of the capacitor. The glow of the bulb:

G1 Physics · Accepted Answer

For the capacitor: X(C) = 1/(ωC) On inserting a dielectric: C increases Therefore: X(C) decreases For the series circuit: Z = √[R² + X(C)²] So impedance decreases. Hence current increases and the bulb glows brighter.