Question 153: AC fundamentals

Question

Given below are two statements:
Statement I : An AC circuit undergoes electrical resonance if it contains either a capacitor or an inductor.
Statement II : An AC circuit containing a pure capacitor or a pure inductor consumes high power due to its non-zero power factor.
In the light of above statements, choose the correct answer form the options given below:

Accepted Answer

Statement I: An AC circuit undergoes electrical resonance if it contains either a capacitor or an inductor.
This statement is incorrect. Electrical resonance occurs in an AC circuit when the capacitive reactance and inductive reactance are equal, causing the impedance of the circuit to be minimum. This typically happens in a series RLC circuit or a parallel RLC circuit. If the circuit contains only a capacitor or an inductor, it cannot undergo electrical resonance as there is no counterpart reactance to balance the impedance.
Statement II: An AC circuit containing a pure capacitor or a pure inductor consumes high power due to its non-zero power factor.
This statement is also incorrect. An AC circuit containing a pure capacitor or a pure inductor will have a power factor of 0, not a non-zero power factor. The power factor of a capacitor is -1, and the power factor of an inductor is +1, but when only considering the reactive components, the power factor is 0. In such a circuit, no real power is consumed, and the circuit only has reactive power. The energy is alternately stored and released by the capacitor and inductor, but no energy is dissipated as heat or used to perform work.
As both statements are incorrect, the correct answer would be an option that states both statements are false.

Answer

Both Statement I and Statement II are false

Answer

Statement I is true but statement II is false

Answer

Statement I is false but statement II is true

Answer

Both Statement I and Statement II are true

AC fundamentals

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