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NEW Extra Class Exam Question Pool

effective 7/01/2016 thru 6/29/2020

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2016-E5A: Resonance and Q: characteristics of resonant circuits: series and parallel resonance; definitions and effects of Q; half-power bandwidth; phase relationships in reactive circuits

2016-E5A01: What can cause the voltage across reactances in series to be larger than the voltage applied to them?

Resonance

Capacitance

Conductance

Resistance



2016-E5A02: What is resonance in an electrical circuit?

The frequency at which the capacitive reactance equals the inductive reactance

The highest frequency that will pass current

The lowest frequency that will pass current

The frequency at which the reactive impedance equals the resistive impedance



2016-E5A03: What is the magnitude of the impedance of a series RLC circuit at resonance?

Approximately equal to circuit resistance

High, as compared to the circuit resistance

Approximately equal to capacitive reactance

Approximately equal to inductive reactance



2016-E5A04: What is the magnitude of the impedance of a circuit with a resistor, an inductor and a capacitor all in parallel, at resonance?

Approximately equal to circuit resistance

Approximately equal to inductive reactance

Low, as compared to the circuit resistance

Approximately equal to capacitive reactance



2016-E5A05: What is the magnitude of the current at the input of a series RLC circuit as the frequency goes through resonance?

Maximum

Minimum

R/L

L/R



2016-E5A06: What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance?

It is at a maximum

It is at a minimum

It equals 1 divided by the quantity 2 times Pi, multiplied by the square root of inductance L multiplied by capacitance C

It equals 2 multiplied by Pi, multiplied by frequency, multiplied by inductance



2016-E5A07: What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

Minimum

Maximum

R/L

L/R



2016-E5A08: What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance?

The voltage and current are in phase

The voltage leads the current by 90 degrees

The current leads the voltage by 90 degrees

The voltage and current are 180 degrees out of phase



2016-E5A09: How is the Q of an RLC parallel resonant circuit calculated?

Resistance divided by the reactance of either the inductance or capacitance

Reactance of either the inductance or capacitance divided by the resistance

Reactance of either the inductance or capacitance multiplied by the resistance

Reactance of the inductance multiplied by the reactance of the capacitance



2016-E5A10: How is the Q of an RLC series resonant circuit calculated?

Reactance of either the inductance or capacitance divided by the resistance

Reactance of either the inductance or capacitance times the resistance

Resistance divided by the reactance of either the inductance or capacitance

Reactance of the inductance times the reactance of the capacitance



2016-E5A11: What is the half-power bandwidth of a parallel resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150?

47.3 kHz

157.8 Hz

315.6 Hz

23.67 kHz



2016-E5A12: What is the half-power bandwidth of a parallel resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118?

31.4 kHz

436.6 kHz

218.3 kHz

15.7 kHz



2016-E5A13: What is an effect of increasing Q in a resonant circuit?

Internal voltages and circulating currents increase

Fewer components are needed for the same performance

Parasitic effects are minimized

Phase shift can become uncontrolled



2016-E5A14: What is the resonant frequency of a series RLC circuit if R is 22 ohms, L is 50 microhenrys and C is 40 picofarads?

3.56 MHz

44.72 MHz

22.36 MHz

1.78 MHz



2016-E5A15: Which of the following can increase Q for inductors and capacitors?

Lower losses

Lower reactance

Lower self-resonant frequency

Higher self-resonant frequency



2016-E5A16: What is the resonant frequency of a parallel RLC circuit if R is 33 ohms, L is 50 microhenrys and C is 10 picofarads?

7.12 MHz

23.5 MHz

23.5 kHz

7.12 kHz



2016-E5A17: What is the result of increasing the Q of an impedance-matching circuit?

Matching bandwidth is decreased

Matching bandwidth is increased

Matching range is increased

It has no effect on impedance matching





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2016-E5B: Time constants and phase relationships: RLC time constants; definition; time constants in RL and RC circuits; phase angle between voltage and current; phase angles of series RLC; phase angle of inductance vs susceptance; admittance and susceptance
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