# Series and Parallel Resonance MCQ

1. A circuit with a resistor, inductor and capacitor in series is resonant of f Hz. If all the component values are now doubled then the new resonant frequency is

1. 2f
2. remains unchanged
3. f/2
4. f/4

2. A high Q coil has a

1. high bandwidth
2. low power factor
3. high losses
4. a flat responses

3. The resonance frequency ω of RLC circuit is defined as

1. $\sqrt{LC}$
2. $\frac{1}{\sqrt{LC}}$
3. $\sqrt{R/LC}$
4. $\sqrt{LC/R}$

4. The phenomena of resonance is used in

2. capacitor
3. transformer
4. amplifier

5. In a series RLC circuit, the magnitude of resonance frequency can be changed by changing the value of

1. R only
2. L only
3. C only
4. L or C

6. Q of a resonant transmission line is

1. Q = L/R
2. Q = ωL/R
3. Q = ωR/L
4. Q = ω/LR

7. For frequencies below the resonant frequency, a parallel LC circuit behaves as a _________ load.

1. inductive
2. resistive
3. capacitive
4. none of these

8. In LCR circuit which one of the following statement is correct?

1. L and R oppose each other
2. R values increases with frequency
3. the inductive reactances increases with frequency
4. the capacitive reactances increases with frequency

9. Q factor of a coil measured by the meter is __________ the actual Q of the coil.

1. equal to
2. somewhat lesser than
3. somewhat higher than
4. twice

10. For a parallel RLC circuit, which of the following statements is not correct?

1. The bandwidth of the circuit decreases, if R is increased
2. The bandwidth of the circuit remains the same if L is increased
3. At resonance, input impedance is a real quantity
4. At resonance, the magnitude of input impedance attains its minimum value

11. Current at resonance in a series circuit is ________ and in a parallel circuit is _________

1. Minimum, maximum
2. Maximum, minimum
3. Maximum, maximum
4. Minimum, minimum

12. In RLC circuits, the electric current at resonance is

1. Maximum in series circuit and minimum in parallel circuit
2. Maximum in parallel circuit and minimum in series circuit
3. Maximum in both the circuits
4. Minimum in both the circuits

13. The elements in RCL series circuit are

1. Resistance only
2. Inductance only
3. Capacitance only
4. Resistance, inductance and capacitance

14. The electric current in an RLC series circuit at resonance is

1. Maximum
2. Minimum
3. Infinity
4. Zero

15. At a frequency less than the resonant frequency

1. Series circuit is capacitive and parallel circuit is inductive
2. Series circuit is inductive and parallel circuit is capacitive
3. Both circuits are inductive
4. Both circuits are capacitive

16. The value of current at resonance in a series RLC circuit is  affected by the value of

1. R
2. C
3. L
1. only i
2. only ii
3. only iii
4. i, ii, and iii

17. In an R-C-L series circuit, during resonance, the impedance will be

1. Zero
2. Minimum
3. Maximum
4. None of these

18. Resonance in RLC series circuit at a frequency

1. $f_r=\frac{1}{\pi\sqrt{LC}}$
2. $f_r=2\pi\sqrt{LC}$
3. $f_r=\frac{R}{2\pi\sqrt{LC}}$
4. $f_r=\frac{1}{2\pi\sqrt{LC}}$

19. The parallel circuit consists of an inductive branch with R and L as its resistance and inductance and a capacitance branch with C farad. The impedance offered by this circuit under resonance condition is given by

1. Z = LCR
2. Z = R/LC
3. Z  = L/CR
4. Z = LC/R