When an alternating voltage of is applied across a device

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

When an alternating voltage of

220\,\text{V}

is applied across a device

P

, a current of

0.25\,\text{A}

flows through the circuit and leads the applied voltage by an angle

\frac{\pi}{2}

radians. When the same voltage source is connected across another device

Q

, the same current is observed in phase with the applied voltage. What is the current when the same source is connected across a series combination of

P

and

Q

? (a)

\frac{1}{4\sqrt{2}}\,\text{A}

lagging in phase by

\frac{\pi}{4}

with voltage (b)

\frac{1}{4\sqrt{2}}\,\text{A}

leading in phase by

\frac{\pi}{4}

with voltage (c)

\frac{1}{\sqrt{2}}\,\text{A}

leading in phase by

\frac{\pi}{4}

with voltage (d)

\frac{1}{4\sqrt{2}}\,\text{A}

leading in phase by

\frac{\pi}{2}

with voltage

Related theory

AC Fundamentals
AC Circuit Elements
AC circuits with R, L, C
AC applied to a capacitor
Alternating Current

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