Principles

Question 1

What will produce a magnetic field?

Answer 1

A current flowing through a conductor.

Question 2

When induced currents produce expanding magnetic fields around conductors in a direction that opposes the original magnetic field, this is known as?

Answer 2

Lenz’s law.

Question 3

What determines the field strength of the magnetic field around a conductor?

Answer 3

The amount of current.

Question 4

They opposition to the creation of magnetic lines of force in a magnetic circuit is know as?

Answer 4

Reluctance

Question 5

Permeability is defined as?

Answer 5

The ratio of magnetic flux density in a substance to the magnetizing force that produces it.

Question 6

What is meant by the term “back EMF”?

Answer 6

A voltage that opposes the applied EMF.

Question 7

What group of metals are the best low-resistance conductors?

Answer 7

Gold, silver, and copper

Question 8

Good conductors with minimum resistance have what type of electrons?

Answer 8

Many free electrons.

Question 9

What formula would calculate the total inductance of inductors in series?

Answer 9

LT = L1 + L2

Question 10

How many degrees are there in one complete sine wave cycle?

Answer 10

360 degrees

Question 11

What type of wave is characterized by a rise time significantly faster than the fall time?

Answer 11

Sawtooth wave

Question 12

What type of wave is made up of sine waves of the fundamental frequency and all the odd harmonics?

Answer 12

Square

Question 13

What type of wave is made up of sine waves at the fundamental frequency and all the harmonics?

Answer 13

Sawtooth wave

Question 14

What is the basic unit of electrical power?

Answer 14

Watt

Question 15

What formula would determine the inductive reactance of a coil if frequency and coil inductance are known?

Answer 15

XL = 2πfL

Question 16

What is the term used to express the amount of electrical energy stored in an electrostatic field?

Answer 16

Joules

Question 17

The product of readings of an AC voltmeter and AC ammeter is called:

Answer 17

Apparent power

Question 18

What is the term for the out-of-phase power associated with inductors and capacitors?

Answer 18

Reactive power

Question 19

Which metal object may be least affected by galvanic corrosion when submerged in seawater?

Answer 19

Stainless steel propeller shaft

Question 20

What metal is usually employed as a sacrificial anode for corrosion control purposes?

Answer 20

Zinc bar

Question 21

What is the relative dielectric constant for air?

Answer 21

1

Question 22

Corrosion resulting from electric current flow between dissimilar metals is called?

Answer 22

Galvanic corrosion

Question 23

Which of these will be most useful for insulation at UHF frequencies?

Answer 23

Mica

Question 24

Skin effect is the phenomenon where?

Answer 24

RF current flows in a thin layer of the conductors, closer to the surface, as frequency increases.

Question 25

How might you reduce the inductance of an antenna coil?

Answer 25

Reduce the number of turns.

Question 26

What is the purpose of a bypass capacitor?

Answer 26

It removes alternating current by providing a low impedance path to ground.

Question 27

What is the easiest voltage amplitude to measure by viewing a pure sine wave signal on an oscilloscope?

Answer 27

Peak-to-peak

Question 28

What is the RMS voltage at a common household electrical power outlet?

Answer 28

117-V AC

Question 29

An AC ammeter indicates?

Answer 29

Effective (RMS) values of current

Question 30

What is the peak voltage at a common household electrical outlet?

Answer 30

165.5 volts

Question 31

By what factor must the voltage of an AC circuit, as indicated on the scale of an AC voltmeter, by multiplied to obtain the peak voltage value?

Answer 31

1.414

Question 32

By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage value?

Answer 32

0.9

Question 33

What are the 5 common materials of descending conductivity?

Answer 33

Silver, copper, aluminum, iron, and lead

Question 34

Halving the cross-sectional area of A conductor will?

Answer 34

Double the resistance.

Question 35

What is the term used to identify an AC voltage would cause the same heating in a resistor as a corresponding value of DC voltage?

Answer 35

Root mean square (RMS)

Question 36

What happens to receive power in a circuit that has both inductors and capacitors?

Answer 36

It alternates between magnetic and electric fields and is not dissipated.

Question 37

Assuming a power source to have a fixed value of internal resistance, maximum power will be transferred to the load when?

Answer 37

The load impedance equals the internal impedance of the source.

Question 38

How do you compute true power (power dissipated in the circuit) in a circuit where AC voltage and current are out of phase?

Answer 38

Multiply apparent power times the power factor.

Question 39

What is the peak voltage at a common household electrical outlet?

Answer 39

165.5 volts

Question 40

What will produce a magnetic field?

Answer 40

A current flowing through a conductor.

Question 41

What are the 2 basic types of junction field-effect transistors?

Answer 41

N-channel and P-channel

Question 42

MOSFETs are manufactured with THIS protective device from static charges and excessive voltages

Answer 42

Zener diode

Question 43

What are the 2 most commonly-used specifications for a junction diode?

Answer 43

Maximum forward current and PIV (peak inverse voltage)

Question 44

A common emitter amplifier has?

Answer 44

More voltage gain than a common collector

Question 45

How does the input impedance of a field-effect transistor compare with that of a bipolar transistor?

Answer 45

A FET has high input impedance; a bipolar transistor has low input impedance.

Question 46

What limits the maximum forward current in a junction diode?

Answer 46

The junction temperature

Question 47

How would you calculate the total capacitance of 3 capacitors in parallel?

Answer 47

CT=C1+C2+C3

Question 48

The opposition to the creation of magnetic lines of force in a magnetic circuit is known as?

Answer 48

Reluctance

Question 49

What is the description of a square wave?

Answer 49

A wave that abruptly changes back and forth between 2 voltages levels for equal amounts of time.

Question 50

What is a sine wave?

Answer 50

A wave whose amplitude at any given instant can be represented by the projection of a point on a wheel rotating at a uniform speed.

Question 51

What device is used to store electrical energy in an electrostatic field?

Answer 51

Capacitor.

Question 52

Which metal object may be least affected by galvanic corrosion when submerged in seawater?

Answer 52

Stainless steel propeller shaft.