Question

An AC voltage source of variable angular frequency $\omega$ and fixed amplitude V connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When $\omega$ is increased

• A. total impedance of the circuit increases
• B. total impedance of the circuit is unchanged
• C. the bulb glows brighter
• D. the bulb glows dimmer

Answer 1

The correct option is C

the bulb glows brighter

$L_{rms}=\frac{V_{rms}}{\sqrt{R^2+\frac{1}{C^2{\omega }^2}}}$

When $\omega$ increases, $I_{rms}$ increases so the bulb glows brighter