question_answer

The value of current at resonance in series LCR circuit is affected by the value of

A)  R only                                  

B)  C only

C)  L only                                  

D)  R, C and L

Correct Answer: A

Solution :

                 Let E be the emf of the series LCR circuit, then current \[(I)\] is given by                 \[I=\frac{E}{Z}\]                                 where Z is impedance.                                 \[Z=\sqrt{{{R}^{2}}+{{\left( \omega L-\frac{1}{\omega C} \right)}^{2}}}\] At resonance \[\omega L=\frac{1}{\omega C}\] \[\therefore \]                  Z = R Hence, current \[I=\frac{E}{R}\], depends on the value of R only.