# RLC Circuits and Resonance MCQ Questions & Answers

RLC Circuits and Resonance MCQs : This section focuses on the "RLC Circuits and Resonance". These Multiple Choice Questions (MCQs) should be practiced to improve the RLC Circuits and Resonance skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

What is the Q (Quality factor) of a series circuit that resonates at 6 kHz, has equal reactance of 4 kilo-ohms each, and a resistor value of 50 ohms?

A. 0.001
B. 50
C. 80
D. 4

Question 2

At resonance, the term bandwidth includes all frequencies that allow what percentage of maximum current to flow?

A. 50
B. 62.3
C. 70.7
D. 95.3

Question 3

How much current will flow in a 100 Hz series RLC circuit if VS = 20 V, RT = 66 ohms, and XT = 47 ohms?

A. 1.05 A
B. 303 mA
C. 247 mA
D. 107 mA

Question 4

What is the range between f1 and f2 of an RLC circuit that resonates at 150 kHz and has a Q of 30?

A. 100.0 kHz to 155.0 kHz
B. 147.5 kHz to 152.5 kHz
C. 4500 kHz to 295.5 kHz
D. 149,970 Hz to 150,030 Hz

Question 5

What is the band pass (F1 – F2) of an RLC filter that resonates at 150 kHz and has a coil Q of 30?

A. 100.0 kHz to 155.0 kHz
B. 147.5 kHz to 152.5 kHz
C. 295.5 kHz to 4500 kHz
D. 149,970 Hz to 150,030 Hz

Question 6

What is the total impedance of a 60 Hz series RLC circuit when XL = 7.5 ohms, XC = 265.3 ohms, and R = 33 ohms?

A. 257.8 ohms
B. 259.9 ohms
C. 290.8 ohms
D. 1989.75 ohms

Question 7

What is the true power consumed in a 30 V series RLC circuit if Z = 20 ohms and R = 10 ohms?

A. 15.0 watts
B. 22.5 watts
C. 30.0 watts
D. 45.0 watts

Question 8

What is the applied voltage for a series RLC circuit when IT = 3 mA, VL = 30 V, VC = 18 V, and R = 1000 ohms?

A. 3.00 V
B. 12.37 V
C. 34.98 V
D. 48.00 V

Question 9

What is the high cutoff frequency for an RLC circuit that resonates at 2000 Hz and has a bandwidth of 250 Hz?

A. 2125 Hz
B. 2250 Hz
C. 1750 Hz
D. 8.0 Hz

Question 10

Current in a series RLC circuit may always be used as:

B. a reference
C. an angle
D. a lagging vector

Question 11

What is the approximate phase angle in a series RLC circuit when VC = 117 V, VR = 14.5 V, and VL = 3.3 V?

A. –45.0 degrees
B. –82.7 degrees
C. –90.0 degrees
D. –172.7 degrees

Question 12

What is the current phase angle for a parallel RLC circuit when IL = 15.3 A, IC = 0.43 A, and IR = 3.5 A?

A. 76.7 degrees
B. –4.25 degrees
C. 88.8 degrees
D. –76.7 degrees

Question 13

What would be the power factor for an RLC circuit that acts inductively?

B. one
C. zero
D. –90 degrees lagging

Question 14

When a full band of frequencies is allowed to pass through a filter circuit to the output, the resonant circuit is called a:

A. low-pass filter
B. high-pass filter
C. band-stop filter
D. bandpass filter

Question 15

When XC = XL the circuit:

A. draws maximum current
B. applied voltage is zero
C. is at resonance
D. draws minimum current

Question 16

At any resonant frequency, what voltage is measured across the two series reactive components?

A. applied
B. reactive
C. zero
D. inductive and capacitive

Question 17

Series RLC voltage or impedance totals must be calculated by:

A. subtracting the values
B. graphing the angles
D. multiplying the values

Question 18

When a parallel circuit resonates it is said to:

A. flywheel
B. oscillate
C. both of the above
D. none of the above

Question 19

In a series RLC circuit the current can be found using:

C. both of the above
D. none of the above

Question 20

Voltage lags current in an RLC circuit when it acts:

A. capacitively
B. resistively
C. inductively
D. resonantly

Question 21

Series RLC impedance or voltage totals must always be calculated by

B. graphing the angles
C. multiplying the values
D. subtracting the values

Question 22

If the bandwidth of a filter increases:

A. Q decreases
B. the roll-off rate increases
C. the half-power frequency decreases
D. the center frequency decreases

Question 23

What effect will a parallel tank have upon final filter current?

A. very little
B. The bandpass frequencies will change.
C. The frequency cutoff will change.
D. The impedance will block output.

Question 24

Which statement best describes reactance in a series RLC circuit?

A. Capacitive reactance is always dominant.
B. Inductive reactance is always dominant.
C. Resistance is always dominant.
D. The larger of the two reactances is dominant.

Question 25

At any resonant frequency, what net voltage is measured across the two series reactive components?

A. Applied voltage
B. Reactive voltage
C. Zero voltage
D. VL + VC voltage