COMEDK · Physics · 23. Alternating Current
An AC voltage source of variable angular frequency \(\omega\) and fixed amplitude \(\mathrm{V}_0\) is connected in series with a capacitance \(\mathrm{C}\) and an electric bulb of resistance \(\mathrm{R}\) (inductance zero). When \(\omega\) is decreased
- A total impedance of the circuit is unchanged
- B the bulb glows brighter
- C the bulb switches off
- D the bulb glows dimmer
Answer & Solution
Correct Answer
(D) the bulb glows dimmer
Step-by-step Solution
Detailed explanation
The impedance \(Z\) of an RC series circuit is given by \(Z = \sqrt{R^2 + X_C^2}\), where \(X_C = \dfrac{1}{\omega C}\) is the capacitive reactance. When the angular frequency \(\omega\) is decreased, the capacitive reactance \(X_C = \dfrac{1}{\omega C}\) increases. Since…
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