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In a purely capacitive AC circuit, the power consumed over a complete cycle is _______.
minimum but not zero
maximum
zero
equal to the apparent power
zero
In a purely capacitive AC circuit, the average power consumed over a complete cycle is zero. This is because capacitors act as energy storage elements rather than energy dissipating elements.
In a purely capacitive AC circuit, the average power consumed over a complete cycle is zero. This is because capacitors act as energy storage elements rather than energy dissipating elements.
Think of a capacitor like a spring: when you push it, it stores energy, and when you let go, it gives that same energy back to the system without losing any as heat.
ELI the ICE man: In an Inductor (L), E leads I. In a Capacitor (C), I leads E.
PavgтАЛ=VrmsтАЛIrmsтАЛcos(╧Х) тАФ Average power formula
╧Х=90┬░ тАФ Phase angle for pure capacitive circuit
In an ideal capacitor, the current leads the voltage by a phase angle of 90┬░ or 2╧АтАЛ radians. The instantaneous power is P=V├ЧI, and the average power over a cycle is PavgтАЛ=VrmsтАЛIrmsтАЛcos(╧Х). Since the phase difference ╧Х=90┬░, the power factor cos(90┬░)=0, leading to zero net power consumption.
A pure capacitor consumes no real power (active power).
Energy is stored in the electric field during one half-cycle and returned to the source during the next half-cycle.
Such a circuit is referred to as 'wattless' because the average power is zero.
Ideal capacitors do not dissipate energy as heat, increasing electrical efficiency in power systems.
Purely capacitive circuits are theoretical; real capacitors have internal resistance (Equivalent Series Resistance or ESR) which causes some power loss.
Power factor correction in industrial AC motors.
Coupling and decoupling circuits in electronics.
Ideal components are assumed to have no internal resistance.
Option B is incorrect because capacitors do not generate power; they only store it.
Option D is incorrect because the apparent power (S=VrmsтАЛIrmsтАЛ) is not zero, but the real power is.
C is correct тАФ In a pure capacitive circuit, the phase shift between voltage and current results in a power factor of zero, leading to no real power consumption.
Always remember that in AC circuits, resistors dissipate power, whereas ideal inductors and capacitors only store and release energy without net consumption.