Basic Electricity

Question 1

The working voltage of a capacitor in an AC circuit should be:
A. Equal to the highest applied voltage.
B. At least 20 percent greater than the highest applied voltage.
C. At least 50 percent greater than the highest applied voltage.

Answer 1

C. At least 50 percent greater than the highest applied voltage.

Question 2

The term that describes the combined resistive forces in an AC circuit is:
A. Resistance.
B. Reactance.
C. Impedance.

Answer 2

C. Impedance.

Question 3

What is the opposition to the flow of AC produced by an electromagnetic field (EMF) with generated back voltage called?
A. Inductive reactance.
B. Capacitive reactance.
C. Mutual inductance.

Answer 3

A. Inductive reactance.

Question 4

Electrostatic fields are also known as:
A. Dielectric fields.
B. Electrostatic fields.
C. Static fields.

Answer 4

A. Dielectric fields.

Question 5

The basis for transformer operation in the use of alternating current is mutual:
A. Inductance.
B. Capacitance.
C. Reactance.

Answer 5

A. Inductance.

Question 6

The opposition offered by a coil to the flow of alternating current (ignoring resistance) is called:
A. Impedance.
B. Reluctance.
C. Inductive reactance.

Answer 6

C. Inductive reactance.

Question 7

What factors strengthen a coil inductor?
A. Limiting and separating the coils.
B. Adding and separating the coils.
C. Adding coils close together.

Answer 7

C. Adding coils close together.

Question 8

An increase in which of the following factors will cause an increase in the inductive reactance of a circuit?
A. Inductance and frequency.
B. Resistance and voltage.
C. Resistance and capacitive reactance.

Answer 8

A. Inductance and frequency.

Question 9

(Refer to figure 1.) when different rated capacitors are connected in series in a circuit, the total capacitance is:
A. Less than the capacitance of the lowest rated capacitor.
B. Greater than the capacitance of the highest rated capacitor.
C. Equal to the sum of all the capacitances.

Answer 9

A. Less than the capacitance of the lowest rated capacitor.

Question 10

Capacitors are sometimes used in DC circuits to:
A. Counteract inductive reactance at specific locations.
B. Smooth out slight pulsations in current/voltage.
C. Assist in stepping voltage and current up and/or down.

Answer 10

B. Smooth out slight pulsations in current/voltage.

Question 11

In an AC circuit, the effective voltage is:
A. Equal to the maximum instantaneous voltage.
B. Greater than the maximum instantaneous voltage.
C. Less than the maximum instantaneous voltage.

Answer 11

C. Less than the maximum instantaneous voltage.

Question 12

The amount of electricity a capacitor can store is directly proportional to the:
A. Distance between the plates and inversely proportional to the plate area.
B. Plate area and is not affected by the distance between the plates.
C. Plate area and inversely proportional to the distance between the plates.

Answer 12

C. Plate area and inversely proportional to the distance between the plates.

Question 13

(Refer to figure 2) What is the total capacitance of a certain circuit containing three capacitors with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectively?
A. .170 uF.
B. 0.125 pF.
C. .0125 uF.

Answer 13

C. .0125 uF.

Question 14

What is the total capacitance of a certain circuit containing three capacitors in parallel with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectively?
A. .170 uF.
B. 0.125 uF.
C. .0125 uF.

Answer 14

A. .170 uF.

Question 15

Convert farads to microfarads by:
A. Multiplying farads by 10 to the power of 6.
B. Multiplying picfarads by 10 to the power of 6.
C. Multiplying microfarads by 10 to the power 6.

Answer 15

A. Multiplying farads by 10 to the power of 6.

Question 16

Convert farads to picofarads by:
A. Multiplying farads by 10 to the power of 12.
B. Multiplying picofarads by 10 to the power of -12.
C. Multiplying microfarads by 10 to the power of 12.

Answer 16

A. Multiplying farads by 10 to the power of 12.

Question 17

Unless otherwise specified, any values given for current or voltage in an AC circuit are assumed to be:
A. Instantaneous values.
B. Effective values.
C. Maximum values.

Answer 17

B. Effective values.

Question 18

When different rated capacitors are connected i parallel in a circuit, the total capacitance is:
A. Less than the capacitance of the lowest rated capacitor.
B. Equal to the capacitance of the highest rated capacitor.
C. Equal to the sum of all the capacitances.

Answer 18

C. Equal to the sum of all the capacitances.

Question 19

When inductors are connected in series in a circuit, the total inductance (where the magnetic fields of each indicator do not affect the others) is:
A. Less than the inductance of the lowest rated inductor.
B. Equal to the inductance of the highest rated inductor.
C. Equal to the sum of the individual inductances.

Answer 19

C. Equal to the sum of the individual inductances.

Question 20

(Refer to figure 3) When more than two inductors of different inductances are connected in parallel in a circuit, the total inductance is:
A. Less than the inductance of the lowest rated inductor.
B. Equal to the inductance of the highest rated inductor.
C. Equal to the sum of the individual inductances.

Answer 20

A. Less than the inductance of the lowest rated inductor.

Question 21

What is the total capacitance of a certain circuit containing three capacitors with capacitances of .25 microfarad, .03 microfarad, and microfarad, respectively?
A. .4uF.
B. .04pF.
C. .04uF.

Answer 21

A. .4uF.

Question 22

Which requires the most electrical power during operation?
A. A 12-volt motor requiring 8 amperes.
B. Four 30-watt lamps in a 12-volt parallel circuit.
C. Two lights requiring 3 amperes each in a 24-volt parallel system.

Answer 22

C. Two lights requiring 3 amperes each in a 24-volt parallel system.

Question 23

How much power must a 24-volt generator furnish to a system which contains the following loads?
One motor (75% efficient) 1/5 HP
Three position lights 20 watts each
One heating element 5 amp
One anti collision light 3 amp
A. 402 watts.
B. 385 watts.
C. 450 watts.

Answer 23

C. 450 watts.

Question 24

A 24-volt, 1-horsepower DC electric motor that is 80 percent efficient requires 932.5 watts. How much power will a 12-volt, 1-horsepower DC electric motor that is 75 percent efficient require?
A. 942.5 watts.
B. 1,305.5 watts.
C. 994.6 watts.

Answer 24

C. 994.6 watts.

Question 25

The potential difference between two conductors which are insulated from each other is measured in: A. Volts. B. Amperes. C. Coulombs.

Answer 25

A. Volts.

Question 26

Which effect does not apply to the movement of electrons flowing in a conductor? A. Magnetic energy. B. Thermal energy. C. Static energy.

Answer 26

C. Static energy.

Question 27

A 24-volt source is required to furnish 48 watts to a parallel circuit consisting of four resistors of equal value. What is the voltage drop across each resistor? A. 12 volts. B. 6 volts. C. 24 volts.

Answer 27

C. 24 volts.

Question 28

When calculating power in a reactive or inductive AC circuit, the true power is: A. More than the apparent power. B. Less than the apparent power in a reactive circuit and more than the apparent power in an inductive circuit. C. Less than the apparent power.

Answer 28

C. Less than the apparent power.

Question 29

(Refer to figure 4) how much power is being furnished to the circuit? A. 575 watts. B. 2,875 watts. C. 2,645 watts.

Answer 29

C. 2,645 watts.

Question 30

(Refer to figure 5) what is the impedance of an AC-series circuit consisting of an inductor with a reactance of 10 ohms, a capacitor with a reactance of 8 ohms? A. 22 ohms. B. 5.29 ohms. C. 10 ohms.

Answer 30

C. 10 ohms.

Question 31

(Refer to figure 6) If resistor R5 is disconnected at the junction of R4 and R3 as shown, what will the ohmmeter read? A. 2.76 ohms. B. 3 ohms. C. 12 ohms.

Answer 31

B. 3 ohms.

Question 32

(Refer to figure 7) If resistor R3 is disconnected at terminal D, what will the ohmmeter read? A. Infinite resistance. B. 10 ohms. C. 20 ohms.

Answer 32

A. Infinite resistance.

Question 33

(Refer to Figure 8) with an ohmmeter connected into the circuit as shown, what will the ohmmeter read? A. 20 ohms. B. Infinite resistance. C. 10 ohms.

Answer 33

C. 10 ohms.

Question 34

(Refer to figure 9) How many instruments (voltmeters and ammeters) are installed correctly? A. Three. B. One. C. Two.

Answer 34

C. Two.

Question 35

The correct way to connect a test voltmeter in a circuit is: A. In series with a unit. B. Between the source voltage and the load. C. In parallel with a unit.

Answer 35

C. In parallel with a unit.

Question 36

What will a voltmeter read if properly connected across a closed switch in a circuit with electrical power on? A. Voltage drop in the component(s) the switch is connected to. B. System voltage. C. Zero voltage.

Answer 36

C. Zero voltage.

Question 37

What does the letter Q symbolize when measuring electrical charges? A. Farad. B. Electron. C. Coulomb.

Answer 37

C. Coulomb.

Question 38

Which term means .001 ampere? A. Microampere. B. Kiloampere. C. Milliampere.

Answer 38

C. Milliampere.

Question 39

A cabin entry light of 10 watts and a dome light f 20 watts are connected in parallel to a 30-volt source. If the voltage across the 10-watts light is measured, it will be: A. Equal to the voltage across the 20-watt light. B. Half the voltage across the 20-watt light. C. One-third of the input voltage.

Answer 39

A. Equal to the voltage across the 20-watt light.

Question 40

A 14-ohm resistor is to be installed in a series circuit carrying .05 ampere. How much power will the resistor be required too dissipate? A. At least .70 milliwatt. B. At least 35 milliwatt. C. Less than .035 watt.

Answer 40

B. At least 35 milliwatt.

Question 41

.002 kV equals: A. 20 volts. B. 2.0 volts. C. .2 volts.

Answer 41

B. 2.0 volts.

Question 42

(Refer to figure 10) what is the measure =d voltage of the series-parallel circuit between terminals A and B? A. 1.5 volts. B. 3.0 volts. C. 4.5 volts.

Answer 42

B. 3.0 volts.

Question 43

(Refer to figure 64) a 24-volt course is required to furnish 48 watts to a parallel circuit consisting of two resistors of equal value. What is the value of each resistor? Rt = E^2/P A. 24 ohms. B. 12 ohms. C. 6 ohms.

Answer 43

A. 24 ohms.

Question 44

Which requires the most electrical power? (1 horsepower = 746 watts) A. A 1/5-horsepower, 24-volt motor which is 75 % efficient. B. Four 30-watt lamps arranged in a 12-volt parallel circuit. C. A 24-volt anti collision light circuit consisting of two light assemblies which require 3 amperes each during operation.

Answer 44

A. A 1/5-horsepower, 24-volt motor which is 75 % efficient.

Question 45

What unit is used to express electrical power? A. Volt. B. Watt. C. Ampere.

Answer 45

B. Watt.

Question 46

What is the basic unit of electrical quantity? A. Electromotive force. B. Ampere. C. Coulomb.

Answer 46

C. Coulomb.

Question 47

What is the operating resistance of a 30-watt light bulb designed for a 28-volt system? A. 1.07 ohms. B. 26 ohms. C. 0.93 ohms.

Answer 47

B. 26 ohms.