Question
What occurs in an LC circuit at resonance?
Answer Options
- A) Current and voltage are equal
- B) Resistance is cancelled
- C) The circuit radiates all its energy in the form of radio waves
- D) Inductive reactance and capacitive reactance cancel
Correct Answer: D
Explanation
An LC circuit (containing an Inductor and a Capacitor) is defined as being at resonance when its inductive reactance (X_L) equals its capacitive reactance (X_C). Since these two forms of reactance are 180^\circ out of phase with each other, they directly oppose and cancel each other out.
When Inductive reactance and capacitive reactance cancel, the circuit’s total impedance becomes purely resistive (Z = R). This cancellation is the fundamental characteristic of resonance and allows the circuit to oscillate freely at the resonant frequency, making LC circuits essential for oscillators and filters.
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