Midterm study

What is a device that opposes a change of voltage? a. an inductor b. a capacitor c. a diode

a capacitor

Two inductors are connected in series to a 120-V, 60-Hz supply. The values of the inductors are 0.175 H and 0.255 H. The total circuit current is _____. a. 0.74 A b. 1.02 A c. 1.85 A d. 3.067 A

0.74A

In a parallel circuit, ET = 277 V, R = 56 kΩ, and XL = 68 kΩ. What is the phase angle (angle theta)? a. 34.56° b. 39.47° c. 50.53° d. 90°

39.47°

The symbol for reactance is _____. a. RL b. XL c. L d. H

Xl

In a parallel circuit, ET = 240 V, R = 47 kΩ, and XL = 50 kΩ. What is the reactive power? a. 0.54 VARs b. 0.89 VARs c. 1.15 VARs d. 1.23 VARs

1.15 VARs

In a parallel circuit, ET = 120 V, R = 8.2 kΩ, and XL = 10 kΩ. What is IL? a. 6.59 mA b. 9.28 mA c. 12 mA d. 14.63 mA

12mA

In a parallel circuit, ET = 120 V, R = 1500 Ω, and XL = 1000 Ω. What is the apparent power? a. 17.31 VA b 24 VA c. 296 VA d. 34.40 VA

17.31 VA

A series RL circuit has a resistance of 270 Ω and an inductive reactance of 155 Ω. How many degrees is angle theta (∠θ)? a. 4.97° b. 5.03° c. 10.14° d. 29.86°

29.86

Two inductors are connected in parallel to a 120-V, 60-Hz supply. The values of the inductors are 0.15 H and 0.225 H. The total inductive reactance is _____. a. 3.54 A b. 4.84 A c. 5.41 A d. 6.12 A

3.54A

A series RL circuit contains two resistors and two inductors. The resistors are 33 Ω and 47 Ω. The inductors have inductive reactances of 60 Ω and 30 Ω. The applied voltage is 120 V. What is the voltage drop on the 33 Ω resistor? a. 32.89V b. 46.84 V c. 55 V d. 60 V

32.89

Two inductors are connected in parallel to a 120-V, 60-Hz supply. The values of the inductors are 1.5 H and 2.5 H. The total inductive reactance is _____. a. 525.5 Ω b. 533.49 Ω c. 942.5 Ω d. 1508 Ω

353.42 is correct but 533.49 is what was on the quiz

What is the peak voltage of a 277 V RMS AC voltage? a. 391.68 V b. 434.85 V c. 576.45 V d. 695.90 V

391.68 V

In a series RL circuit ET = 120 V, R = 150 Ω, and XL = 270 Ω. What is the reactive power? 36.62 VARs 40.75 VARs 42.64 VARs 53.39 VARs

40.75 VARs

A series RL circuit contains two resistors and two inductors. The resistors are 27 Ω and 47 Ω. The inductors have inductive reactances of 50 Ω and 40 Ω. The applied voltage is 120 V. What is the voltage drop on the inductor that has 40 Ω of reactance? a. 28.41 V b. 41.2 V c. 51.5 V d. 67.81 V

41.2

You connect a clamp-on ammeter and a voltmeter to a series RL circuit powered by a 60-Hz circuit. The voltage reads 120 V and the current is 0.715 A. The resistor is 150 Ω. What is the true power? a. 65.8 W b. 76.68 W c. 86 W d. 167.83 W

76.68

A series RL circuit has two resistors and two inductors. The resistors dissipate 7 W and 12 W. The inductive powers are 15 VARs and 8 VARs. The applied voltage is 240 V. How much is the circuit current? a. 8.045 A b. 10.43 A c. 19.83 A d. 22.63 A

8.045

Both AC and DC can be transformed. a. True b. False

False

The total current-limiting effect is called _____. a. reluctance b. impedance c. resistive reactance d. inductive resistance

Impedance

When a magnetic field continually changes magnitude and direction, a voltage is continually being induced in the coil. This voltage is called _____ voltage. a. conducted b. induced c. applied d. inductive

Induced

Circuits are generally considered to contain _____ when any type of load that contains a coil is used. a. inductance b. reactance c. resistance d. volt-amperes

Inductance

The square root of the mean of the square of the instantaneous currents is known as the _____. a. RMS b. peak c. peak-to-peak d. average

RMS

The current-limiting property of an inductor is called _____. a. resistance b. inductance c. reactance d. henrys

Reactance

In a series circuit, the total _____ is equal to the sum of the individual resistors. a. current b. amperage c. voltage d. resistance

Resistance

The_____ effect occurs when AC induces eddy currents into the conductor, which cause the electrons to be repelled toward the outer surface of the conductor. a. insulation b. phasing c. skin d. resistance

Skin

Power factor (PF) is the ratio of the _____ power to the _____ power. a. true; apparent b. apparent; true c. apparent; reactive d. reactive; apparent

True; Apparent

Of the different power values in an RL circuit, which one is known as wattless power? a. VA b. VARs c. W

VARs

The symbol for reactive power of an inductor is _____. a. W b. VA c. VARs d. P

VARs

In a capacitor, the voltage difference between the plates controls the . a. area of the plates b. thickness of the dielectric c. amount of dielectric stress d. amount of current flow through the capacitor

amount of dielectric stress

Each complete waveform of 360° is called a _____. a. cycle b. hertz c. frequency d. rotation

cycle

Increasing the surface area of the plates will cause the capacitance of a capacitor to . a. decrease b. increase c. stay the same

increase

In some capacitors, there is a small amount of current that flows from one plate, through the dielectric material to the other plate. This current is called current. a. leakage b. conduction c. electrostatic d. electrolytic

leakage

A capacitor is constructed by separating two metal conductors known as with an insulating material known as a(n) _____. a. plates; dielectric b. dielectrics; plate c. electrolytes; ceramic d. ceramics; electrolyte

plates; dielectric

When AC voltage is rectified and converted into DC, the resulting waveform is normally not pure, flat DC. The pulses that occur are called _____. a. harmonics b. cosines c. ripples d. peaks

ripples

In a capacitor, the amount of dielectric stress is proportional to the . a. distance between the plates b. thickness of the dielectric c. current flow through the capacitor d. voltage difference between the plates

voltage difference between the plates

The amplitude of a waveform is measured from _____. a. peak-to-peak b. zero to the highest value obtained in either direction c. zero to the RMS level d. zero to the effective level

zero to the highest value obtained in either direction

An inductor has an inductive reactance of 12 Ω, and a wire resistance of 16 Ω. What is the impedance of the inductor? a. 4Ω b. 20 Ω c. 28 Ω d. 400 Ω

20Ω

What is the average voltage of a full-wave rectified 240 V RMS AC voltage? a. 216.17 V b. 252.88 V c. 276.32 V d. 332.75 V

216.17 V

An inductor is connected to a 120-V, 60-Hz supply. The current in the circuit is 2.4 A. What is the inductive reactance? a. 57.08 Ω b. 104.8 Ω c. 288 Ω d. 904.8 Ω

50Ω is correct but on the quiz it was 904.8Ω

In a parallel circuit, ET = 240 V, R = 30 Ω, and XL = 40 Ω. What is the power factor? a. 33% b. 75% c. 80% d. 90%

80%

If an AC waveform is rectified and converted into DC, the voltage value that results is the _____ value. a. average b. peak c. peak-to-peak d. effective

average

The unit of inductance is the _____. a. reactance b. henry c. ohm d. hertz

henry

In a parallel circuit, ET = 240 V, R = 27 kΩ, and XL = 47 kΩ. What is IT? a. 3.24 mA b. 10.25 mA c. 18.89 mA d. 50.11 mA

10.25mA

In a parallel circuit, ET = 240 V, R = 5.6 kΩ, and XL = 3.6 kΩ. What is P? a. 6.26 W b. 8.65 W c. 9 W d. 10.28 W

10.28

In a parallel circuit, ET = 240 V, R = 30 Ω, and XL = 40 Ω. What is IT? a. 3.43 A b. 6 A c. 8.43 A d. 10 A

10A

An inductor with an inductance of three henrys (H) is to be connected to a 60 Hz circuit. What will the inductive reactance be? a. 180 Ω b. 360 Ω c. 565 Ω d. 1131 Ω

1131

In a parallel circuit, ET = 240 V, R = 400 Ω, and XL = 300 Ω. What is P? a. 82.29 W b. 115.2 W c. 122 W d. 144 W

144W

A series RL circuit contains two resistors and two inductors. The resistors are 43 Ω and 54 Ω. The inductors have inductive reactances of 70 Ω and 40 Ω. The total impedance is _____. a. 52.15 Ω b. 67.20 Ω c. 84.94 Ω d. 146.66 Ω

146.66 Ω

In a parallel circuit, ET = 240 V, R = 330 Ω, and XL = 420 Ω. What is Z? a. 120 Ω b. 170 Ω c. 259.62 Ω d. 534.13 Ω

259.62

In a parallel circuit, ET = 120 V, R = 30 Ω, and XL = 40 Ω. What is IL? a. 1.71 A b. 2.4 A c. 3 A d. 4 A

3A

In a parallel circuit, ET = 120 V, R = 30 Ω, and XL = 40 Ω. What is IR? a. 1.71 A b. 2.4 A c. 3 A d. 4 A

4 A

In a DC circuit, the product of volts times the amperes is called the _____ power. a. apparent b. reactive c. true d. inductive

True

The amount of resistance compared with the inductive reactance determines the _____ of the coil. a. power factor (PF) b. quality (Q) c. phase angle (θ) d. reactance (X)

b. quality (Q)

In a parallel circuit, ET = 120 V, R = 3.3 kΩ, and XL = 4 kΩ. What is IR? a. 16.44 mA b. 23.14 mA c. 30 mA d. 36.36 mA

d. 36.36 mA

In a pure inductive circuit, current _____. a. lags voltage by 90° b. leads voltage by 90° c. is in phase with voltage d. lags voltage by 180°

lags voltage by 90°

Square waves are generally produced by electronic devices called _____. a. converters b. alternators c. oscillators d. rectifiers

oscillators

What type of load contains pure resistance? a. capacitive b. inductive c. reactive d. resistive

resistive

Rotating machines normally produce a waveform called a _____ wave. a. cosine b. linear c. sine d. pulsating

sine

What is the most common of all AC waveforms? a. triangle b. sine c. pulsating d. cosine

sine

What is the RMS value of an AC voltage that has a 480 V peak? a. 278.72 V b. 305.76 V c. 339.46 V d. 453.53 V

339.46 V

Two capacitors, a 20 μF and a 30 μF, are connected in series. What is the total capacitance? a. 12 μF b. 50 μF

12uF

A series RL circuit contains two resistors and two inductors. The resistors are 33 Ω and 47 Ω. The inductors have inductive reactances of 60 Ω and 30 Ω. Angle theta is _____. a. 48.37° b. 52.27° c. 63.97° d. 72.55°

48.37

Two capacitors, a 20 μF and a 30 μF, are connected in parallel. What is the total capacitance? a. 12 μF b. 50 μF

50uF

Three capacitors, a 12 μF, a 20 μF and a 30 μF, are connected in series. What is the total capacitance? a. 6 μF b. 62 μF

6uF

In a series RL circuit, ET = 120 V, R = 40 Ω, and XL = 30 Ω. How much is EL? a. 72 V b. 78.57 V c. 86 V d. 91.43 V

72V

An inductor has an inductive reactance of 64 Ω, and a wire resistance of 36 Ω. What is the impedance of the inductor? a. 10 Ω b. 28 Ω c. 73.4 Ω d. 82.92 Ω

73.4

To help overcome the problem of skin effect in high-frequency circuits, conductors with a large amount of _____ must be used.

Surface area

Of the different power values in an RL circuit, which one is known as apparent power? a. VA b. VARs c. W

VA

Of the different power values in an RL circuit, which one is known as quadrature power? a. VA b. W c. VARs

VARs

Volt-amperes-reactive is used to measure the _____ in a pure inductive circuit. a. watts b. reactive power c. volt amperes d. joules

b. reactive power

The material between a capacitor's plates is rated by a value called the . a. dielectric constant b. magnetic constant c. dielectric variable d. magnetic variable

dielectric constant

Energy in a capacitor is stored as a(n) . a. electrostatic charge b. magnetic field c. electromagnetic field d. circulating current

electrostatic charge

The number of cycles completed in one second is called a _____. a. cycle b. hertz c. frequency d. rotation

frequency

Frequency is measured in _____. a. watts b. hertz c. amperes d. voltage

hertz

When current rises and falls at the same rate as the voltage and reverses the direction of flow when the voltage reverses polarity, the current is said to be _____ with the voltage. a. in phase b. out of phase c. in leading phase d. in lagging phase

in phase

The maximum point of a waveform is called the _____. a. RMS b. peak c. peak-to-peak d. effective

peak

In a series RL circuit, the angle between the voltage and current is called angle theta (∠θ). The cosine of the angle is equal to the _____. a. watts b. power factor c. VARs d. volt-amperes

power factor

An inductor is connected to a 60 Hz circuit. The inductive reactance is 75.4 Ω. What is the inductance of the inductor? a. 0.2 H b. 5 H c. 284 H d. 4524 H

0.2H

A series RL circuit contains two resistors. The resistors are 33 Ω and 47 Ω. When calculating the circuit values, the total resistance used is _____. a. 56Ω b. 60 Ω c. 68 Ω d. 80 Ω

80Ω

The symbol XL stands for _____. a. resistance b. inductive resistance c. inductive reactance d. resistive reactance

inductive reactance

What type of AC waveform features voltage rising at a constant rate with respect to time? a. cosine b. linear c. sine d. pulsating

linear

What is the basic unit of capacitance? a. henry b. farad c. ohm d. coulomb

Farad

In a parallel circuit, ET = 208 V, R = 33 kΩ, and XL = 82 kΩ. What is the apparent power? a. 0.14 VA b. 0.31 VA c. 1.22 VA d. 1.41 VA

1.41 VA

In a parallel circuit, ET = 277 V, R = 33 kΩ, and XL = 42 kΩ. What is Z? a. 13.41 kΩ b. 22.48 kΩ c. 25.95 kΩ d. 38.48 kΩ

25.95

In a parallel circuit, ET = 120 V, R = 30 Ω, and XL = 60 Ω. What is the phase angle (angle theta)? a. 13.49° b. 26.51°

26.51

In a series RL circuit, ET = 120 V, R = 30 Ω, and XL = 40 Ω. What is the apparent power? a. 17.92 VA b. 172.8 VA c. 230.4 VA d. 288 VA

288 VA

In a parallel circuit, ET = 208 V, R = 39 kΩ, and XL = 24 kΩ. What is the power factor? a. 31.61% b. 52.4% c. 85% d. 95%

52.4%

Three capacitors, a 12 μF, a 20 μF and a 30 μF, are connected in parallel. What is the total capacitance? a. 6 μF b. 62 μF

62uF

What is the unit of measure for the power delivered to the load in a DC circuit? a. hertz b. volt-amperes c. VARs d. watts

Watts

In a parallel circuit, the voltage across the resistor and the voltage across the inductor are. a. in phase b. 180° out of phase c. less than 90° out of phase with the resistor voltage leading d. less than 90° out of phase with the resistor voltage lagging

in phase

An inductor is connected to a 240-V, 60-Hz supply. The current in the circuit is 5 A. What is the inductance of the inductor? a. .0048 H b. .0075 H c. .1185 H d. .127 H

.127H

In a parallel circuit, the supply voltage is 120 V, 60 Hz. The resistance is 30 Ω and the inductive reactance is 40 Ω. What is the value of the inductor? a. 0.106 H b. 0.196 H c. 0.233 H d. 0.363 H

0.106H

In a series RL circuit, ET = 120 V, R = 500 Ω, and XL = 500 Ω. What is the true power? a. 8.8 W b. 14.4 W c. 17.2 W d. 20.36 W

14.4

In a series RL circuit, ET = 120 V, R = 40 Ω, and XL = 30 Ω. What is ER? a. 72 V b. 88.57 V c. 96 V d. 151.43 V

96V

Two inductors are connected in series to a 120-V, 60-Hz supply. The values of the inductors are 1.5 H and 2.5 H. The total inductive reactance is _____. a. 42.5 Ω b. 365.5 Ω c. 553.44 Ω d. 1508 Ω

1508Ω

A term used to indicate the same value as the RMS value is the _____ value. a. average b. peakAC wav c. peak-to-peak d. effective

Effective

In a parallel circuit, ET = 120 V, R = 470 Ω, and XL = 500 Ω. What is the reactive power? a. 20.98 VARs b. 28.8 VARs c. 34.85 VARs d. 39.64 VARs

28.8

In a parallel circuit, the current flow through the inductor will be . a. in phase b. 180° out of phase c. 90° out of phase with the voltage d. less than 90° out of phase with the resistor current lagging

90° out of phase with the voltage

A series RL circuit contains two resistors. The resistors are 60 Ω and 30 Ω. When calculating the circuit values, the total resistance used is _____. a. 30 Ω b. 60 Ω c. 80 Ω d. 90 Ω

90Ω

Dividing a circuit's total applied voltage by the total impedance results in the total _____. a. current b. power c. VA d. VARs

Current

What letter symbolizes the farad? a. C b. Q c. F d. V

F