When an alternating voltage of 220V is applied across a device X, a current of 0.5A

flows through the circuit and is in phase with the applied voltage. When the same

voltage is applied across another device Y the same current flows through the

circuit but it leads the applied voltage by /2 rad.

(a) Name the devices X and Y.

(b) Calculate the current flowing in the circuit when same voltage is applied across

the series combinations of X and Y.

v = 220 V

I = 0.5 A

1) X is resistor, Y is Capacitor

2) R = Xc as the same current is flowing in both cases.

When connected in series, net impedance= Z = $\sqrt{{R}^{2}+{{X}_{c}}^{2}}=\sqrt{2{R}^{2}}=\sqrt{2}R=\sqrt{2}V/I=220\sqrt{2}/0.5=622.25ohm$

voltage applied is same

so current is : V/Z =220/622.25 = 0.35355 Ampere

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