Question

Same current is flowing in two alternating circuits. The circuit contains only inductance and the other contains only a capacitor. If the frequency of the emf of ac is increased, the effect on the value of the current will be

• A. increase in the first circuit and decreases in the other
• B. increase in both the circuit and decrease in both the circuit
• C. decrease in both the circuit
• D. decrease in first circuits and increase in the other

Answer 1

Answer: (D)

decrease in first circuits and increase in the other

$\omega =2\pi f$

Current in inductive circuit $=\left|\frac{V}{L\omega }\right|=\left|\frac{V}{L2\pi f}\right|\to$ Current decreases as frequency increases

Current in capacitve circuit $=\left|\frac{V}{1/C\omega }\right|=\left|\frac{VC\omega }{1}\right|=\left|VC2\pi f\right|\to$ Current increases as frequency increases