(a) Define: (i) reactance; (ii) impedance. (b)(i) Explain resonant frequency of an RLC circuit. (ii) Explain the statement — the power supply voltage of a source is 230V (c) A source of e.m.f 240V and frequency 50 Hz is connected to a series arrangement of a resistor, an inductor and a capacitor. When the current in the capacitor is 10A, the potential difference across the resistor is 140 V and that across the inductor is 50 V. Calculate the: (i) potential difference across the capacitor (ii) capacitance of the capacitor; (iii) inductance of the indicator. (d) Draw and label one vector diagram for the potential differences across the inductor, the capacitor and the resistor in (c) above.
Explanation
(a)(i) Reactance s the opposition in ohms to the alternating current by an inductor, a capacitor or both. (ii) Impedance is the total opposition is ohms to the alternating current by a combination of resistor as well as a capacitor or an inductor.
(b)(i) Resonant frequency fo is to frequency at which the current in the circuit has a maximum value. fo = (ii) This means that the root mean square value of the voltage is 230v. The actual voltage lies between Vo and -Vo where the voltage amplitude or peak voltage Vo.
