Question

A coil of resistance 20 Ω and self-inductance 10 mH is connected to an ac source of frequency 1000/π Hz. The phase difference between current in the circuit and the source voltage is :

An inductor, a capacitor and a resistor are connected in series across an ac source of voltage. If the frequency of the source is decreased gradually, the reactance of :

(i) A resistor and a capacitor are connected in series to an ac source v = vm sin ωt. Derive an expression for the impedance of the circuit. (ii) When does an inductor act as a conductor in a circuit ? Give reason for it. (iii) An electric lamp is designed to operate at 110 V dc and 11 A current. If the lamp is operated on 220 V, 50 Hz ac source with a coil in series, then find the inductance of the coil.

An inductor of resistance 5 Ω and self-inductance 25 mH is connected across an ac source of angular frequency 200 rad s⁻¹. The phase angle between the voltage and the current is :