How many questions are in subelement E5?

The current pool contains 49 questions in subelement E5.

extra pool

Subelement E5 question review

All 49 official questions with the exact winning phrase marked.

E5A01E5A

What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit?

AResonance

Why this answer

The key fact is Resonance. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5A02E5A

What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries, and C is 40 picofarads?

C3.56 MHz

Why this answer

The key fact is 3.56 MHz. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5A03E5A

What is the magnitude of the impedance of a series RLC circuit at resonance?

DApproximately equal to circuit resistance

E5A04E5A

What is the magnitude of the impedance of a parallel RLC circuit at resonance?

AApproximately equal to circuit resistance

E5A05E5A

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

AMatching bandwidth is decreased

E5A06E5A

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

BIt is at a maximum

Why this answer

The key fact is It is at a maximum. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5A07E5A

What is the magnitude of the current at the input of a parallel RLC circuit at resonance?

AMinimum

Why this answer

The key fact is Minimum. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5A08E5A

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

CThe voltage and current are in phase

Why this answer

The key fact is The voltage and current are in phase. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5A09E5A

How is the Q of an RLC parallel resonant circuit calculated?

CResistance divided by the reactance of either the inductance or capacitance

E5A10E5A

What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries, and C is 10 picofarads?

A7.12 MHz

Why this answer

The key fact is 7.12 MHz. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5A11E5A

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

C47.3 kHz

Why this answer

The key fact is 47.3 kHz. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

P = E × I

E5A12E5A

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

C31.4 kHz

Why this answer

The key fact is 31.4 kHz. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

P = E × I

E5A13E5A

What is an effect of increasing Q in a series resonant circuit?

CInternal voltages increase

E5B01E5B

What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the applied voltage or to discharge to 36.8% of its initial voltage?

BOne time constant

Why this answer

The key fact is One time constant. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Capacitors store energy in an electric field.

E = I × R

E5B02E5B

What letter is commonly used to represent susceptance?

E5B03E5B

How is impedance in polar form converted to an equivalent admittance?

BTake the reciprocal of the magnitude and change the sign of the angle

E5B04E5B

What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors, all in parallel?

D220 seconds

Why this answer

The key fact is 220 seconds. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Capacitors store energy in an electric field.

E = I × R

E5B05E5B

What is the effect on the magnitude of pure reactance when it is converted to susceptance?

DIt is replaced by its reciprocal

E5B06E5B

What is susceptance?

CThe imaginary part of admittance

E5B07E5B

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 500 ohms, R is 1 kilohm, and XL is 250 ohms?

C14.0 degrees with the voltage lagging the current

Why this answer

The key fact is 14.0 degrees with the voltage lagging the current. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5B08E5B

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 300 ohms, R is 100 ohms, and XL is 100 ohms?

A63 degrees with the voltage lagging the current

Why this answer

The key fact is 63 degrees with the voltage lagging the current. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5B09E5B

What is the relationship between the AC current through a capacitor and the voltage across a capacitor?

DCurrent leads voltage by 90 degrees

Why this answer

The key fact is Current leads voltage by 90 degrees. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Capacitors store energy in an electric field.

E = I × R

E5B10E5B

What is the relationship between the AC current through an inductor and the voltage across an inductor?

AVoltage leads current by 90 degrees

Why this answer

The key fact is Voltage leads current by 90 degrees. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Inductors store energy in a magnetic field.

E = I × R

E5B11E5B

What is the phase angle between the voltage across and the current through a series RLC circuit if XC is 25 ohms, R is 100 ohms, and XL is 75 ohms?

B27 degrees with the voltage leading the current

Why this answer

The key fact is 27 degrees with the voltage leading the current. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5B12E5B

What is admittance?

AThe inverse of impedance

E5C01E5C

Which of the following represents pure capacitive reactance of 100 ohms in rectangular notation?

A0 - j100

Why this answer

The key fact is 0 - j100. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5C02E5C

How are impedances described in polar coordinates?

CBy magnitude and phase angle

E5C03E5C

Which of the following represents a pure inductive reactance in polar coordinates?

CA positive 90 degree phase angle

E5C04E5C

What type of Y-axis scale is most often used for graphs of circuit frequency response?

DLogarithmic

E5C05E5C

What kind of diagram is used to show the phase relationship between impedances at a given frequency?

CPhasor diagram

E5C06E5C

What does the impedance 50 - j25 ohms represent?

B50 ohms resistance in series with 25 ohms capacitive reactance

Why this answer

The key fact is 50 ohms resistance in series with 25 ohms capacitive reactance. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5C07E5C

Where is the impedance of a pure resistance plotted on rectangular coordinates?

DOn the horizontal axis

Why this answer

The key fact is On the horizontal axis. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5C08E5C

What coordinate system is often used to display the phase angle of a circuit containing resistance, inductive, and/or capacitive reactance?

DPolar coordinates

Why this answer

The key fact is Polar coordinates. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5C09E5C

When using rectangular coordinates to graph the impedance of a circuit, what do the axes represent?

AThe X axis represents the resistive component, and the Y axis represents the reactive component

E5C10E5C

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 400-ohm resistor and a 38-picofarad capacitor at 14 MHz?

BPoint 4

Why this answer

The key fact is Point 4. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Capacitors store energy in an electric field.

E = I × R

E5C11E5C

Which point in Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and an 18-microhenry inductor at 3.505 MHz?

BPoint 3

Why this answer

The key fact is Point 3. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Inductors store energy in a magnetic field.

E = I × R

E5C12E5C

Which point on Figure E5-1 best represents the impedance of a series circuit consisting of a 300-ohm resistor and a 19-picofarad capacitor at 21.200 MHz?

APoint 1

Why this answer

The key fact is Point 1. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Capacitors store energy in an electric field.

E = I × R

E5D01E5D

What is the result of conductor skin effect?

AResistance increases as frequency increases because RF current flows closer to the surface

E5D02E5D

Why is it important to keep lead lengths short for components used in circuits for VHF and above?

BTo minimize inductive reactance

E5D03E5D

What is the phase relationship between current and voltage for reactive power?

CThey are 90 degrees out of phase

Why this answer

The key fact is They are 90 degrees out of phase. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

E = I × R

E5D04E5D

Why are short connections used at microwave frequencies?

BTo reduce phase shift along the connection

E5D05E5D

What parasitic characteristic causes electrolytic capacitors to be unsuitable for use at RF?

CInductance

E5D06E5D

What parasitic characteristic creates an inductor’s self-resonance?

DInter-turn capacitance

E5D07E5D

What combines to create the self-resonance of a component?

BThe component’s nominal and parasitic reactance

E5D08E5D

What is the primary cause of loss in film capacitors at RF?

DSkin effect

E5D09E5D

What happens to reactive power in ideal inductors and capacitors?

BEnergy is stored in magnetic or electric fields, but power is not dissipated

Why this answer

The key fact is Energy is stored in magnetic or electric fields, but power is not dissipated. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

Memory hook: Capacitors store energy in an electric field.

P = E × I

E5D10E5D

As a conductor’s diameter increases, what is the effect on its electrical length?

DIt increases

E5D11E5D

How much real power is consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

B100 watts

Why this answer

The required value is 100 watts. Keep the units with the number so a nearby distractor cannot pull you away from the result.

E = I × R

E5D12E5D

What is reactive power?

DWattless, nonproductive power

Why this answer

The key fact is Wattless, nonproductive power. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.

P = E × I