2. When an alternating voltage of 220 V is applied across a device P, a current of 0.25 A. flows through the circuit and it leads the applied voltage by an angle π/2 radian. When the same voltage source is connected across another device Q, the same current is observed in the circuit but in phase with the
applied voltage. The current when the same source is connected across a series combination of P and Q is
(a) 1/4√2
A lagging in phaseby π/4 with voltage
(b) 1/4√2 leading in phase by π/4 with voltage
(c) 1/√2
A leading in phase by π/4 with voltage
(d) 1/4√2
A leading in phase by π/2 with voltage

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Solution

P must be a capacitor
XC=Vrmsirms
=2200.25
= 880v
Q must be a resistor
R=2200.25=880Ω
P – Q will be a RC ckt.
Z=√R2+X2C=880√2Ωirms=220880√2=14√2Atanϕ=XCR=880880=1⇒ϕ=45∘

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P must be a capacitor XC=Vrmsirms =2200.25 = 880v Q must be a resistor R=2200.25=880Ω P – Q will be a RC ckt. Z=√R2+X2C=880√2Ωirms=220880√2=14√2Atanϕ=XCR=880880=1⇒ϕ=45∘

P must be a capacitor
XC=Vrmsirms
=2200.25
= 880v
Q must be a resistor
R=2200.25=880Ω
P – Q will be a RC ckt.
Z=√R2+X2C=880√2Ωirms=220880√2=14√2Atanϕ=XCR=880880=1⇒ϕ=45∘