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

- 2f
- remains unchanged
- f/2
- f/4

2. A high Q coil has a

- high bandwidth
- low power factor
- high losses
- a flat responses

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

- $\sqrt{LC}$
- $\frac{1}{\sqrt{LC}}$
- $\sqrt{R/LC}$
- $\sqrt{LC/R}$

4. The phenomena of resonance is used in

- radio
- capacitor
- transformer
- amplifier

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

- R only
- L only
- C only
- L or C

6. Q of a resonant transmission line is

- Q = L/R
- Q = ωL/R
- Q = ωR/L
- Q = ω/LR

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

- inductive
- resistive
- capacitive
- none of these

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

- L and R oppose each other
- R values increases with frequency
- the inductive reactances increases with frequency
- the capacitive reactances increases with frequency

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

- equal to
- somewhat lesser than
- somewhat higher than
- twice

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

- The bandwidth of the circuit decreases, if R is increased
- The bandwidth of the circuit remains the same if L is increased
- At resonance, input impedance is a real quantity
- 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 _________

- Minimum, maximum
- Maximum, minimum
- Maximum, maximum
- Minimum, minimum

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

- Maximum in series circuit and minimum in parallel circuit
- Maximum in parallel circuit and minimum in series circuit
- Maximum in both the circuits
- Minimum in both the circuits

13. The elements in RCL series circuit are

- Resistance only
- Inductance only
- Capacitance only
- Resistance, inductance and capacitance

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

- Maximum
- Minimum
- Infinity
- Zero

15. At a frequency less than the resonant frequency

- Series circuit is capacitive and parallel circuit is inductive
- Series circuit is inductive and parallel circuit is capacitive
- Both circuits are inductive
- Both circuits are capacitive

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

- R
- C
- L

- only i
- only ii
- only iii
- i, ii, and iii

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

- Zero
- Minimum
- Maximum
- None of these

18. Resonance in RLC series circuit at a frequency

- $f_r=\frac{1}{\pi\sqrt{LC}}$
- $f_r=2\pi\sqrt{LC}$
- $f_r=\frac{R}{2\pi\sqrt{LC}}$
- $f_r=\frac{1}{2\pi\sqrt{LC}}$

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

- Z = LCR
- Z = R/LC
- Z = L/CR
- Z = LC/R

20. Power factor of a parallel RLC circuit at resonance is

- Unity
- Zero
- 0.0707 leading
- 0.707 lagging