# AC Circuit - R-L-C Circuit objective questions (mcq) and answers

21.  An R-L-C series circuit has f1 and f2 as the resonant frequency. The selectivity of the circuit is given by

A. f1 + f2/fr

B. f2 - f1/2fr

C. f2 - f1/fr

D. None of the above

C. f2 - f1/fr

22.  In an R-L-C series resonance circuit, if inductance of the circuit is made double and the capacitance is made half, which of the following will be affected ?

A. Resonant frequency

B. Selectivity of the circuit

C. Current at resonant frequency

D. Impedance at resonant frequency

B. Selectivity of the circuit

23.  When resonant frequency for an R-L-C parallel circuit is given by 1/2 pi root LC, the essential condition is that

A. Inductance must be non-resistive

B. Capacitance must be non-leaky

C. Current is minimum at resonance

D. All of the above

D. All of the above

24.  A series R-L-C circuit is switched on to a step voltage V at t = 0. What are the initial and final values of the current in the circuit, respectively?

A. V/R , V/R

B. Zero, infinity

C. Zero, Zero

D. Zero, V/R

C. Zero, Zero

25.  A parallel circuit is said to be in resonance when the admittance is purely

A. Capacitive

B. Inductive

C. Susceptive

D. Conductive