question_answer

An AC voltage source of variable angular frequency \[\omega \] and fixed amplitude \[{{V}_{0}}\] is connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When \[\omega \] is increased

A) the bulb glows dimmer

B) the bulb glows brighter

C) total impedance of the circuit is unchanged

D) total impedance of the circuit increases

Correct Answer: B

Solution :

\[{{I}_{rms}}=\frac{{{V}_{rms}}}{\sqrt{{{R}^{2}}+{{\left( \frac{1}{\omega C} \right)}^{2}}}}\] As \[\omega \] increases, \[{{I}_{rms}}\] increases. Therefore the bulb glows brighter.