Question: Q. 5. A device ’ $X$ ’ is connected to an ac source $V=V_{0}$ $\sin \omega t$. The variation of voltage, current and power in one complete cycle is shown in the following figure.
U] [CBSE SQP 2015-2016]
(i) Which curve shows power consumption over a full cycle?
(ii) Identify the device ’ $X$ ‘.
Show Answer
Solution:
Ans. (i) $A$
$1 / 2$
(ii) Capacitor
[CBSE Marking Scheme 2016] 11/2
Detailed Answer :
(i) Power’s frequency is double of current or voltage frequency.
(ii) From the graph, the phase difference between $V$ and $I$ is $\frac{\pi}{2}$ so device ’ $X$ ’ may be an inductor ( $L$ ) or capacitor (C) but since current (graph $C$ ) leads the voltage (graph $B$ ), device is capacitor.
