An RLC series circuit, connected to a source , is at resonance.Then:
A)the voltage across R is zero
B)the voltage across R equals the applied voltage
C)the voltage across C is zero
D)the voltage across L equals the applied voltage
E)the applied voltage and current differ in phase by 90°

Question

An RLC series circuit, connected to a source  , is at resonance.Then:
A)the voltage across R is zero 
B)the voltage across R equals the applied voltage 
C)the voltage across C is zero 
D)the voltage across L equals the applied voltage 
E)the applied voltage and current differ in phase by 90°

Quizplus · Accepted Answer

At resonance, the impedance of the circuit is purely resistive and equal to the resistance R. Therefore, the voltage across R is equal to the applied voltage and is not zero. The voltage across C and L, on the other hand, cancel each other out, so they are not equal to the applied voltage. The phase difference between the current and voltage is 0 degrees at resonance, not 90 degrees.

An RLC Series Circuit, Connected to a Source