NAVEDTRA 14174A, NEETS Mod. 2, Ch.1

Question 1

Which type of current regularly changes direction?

Answer 1

Alternating

Question 2

What is the amplitude of direct current in a wire when a coulomb of electrons moves past a point in a wire in one second and all of the electrons are moving in the same direction?

Answer 2

One ampere

Question 3

Which type of current is practically used by all modern commercial electric power companies?

Answer 3

Alternating

Question 4

Which type of device can step up or down alternating voltages amplitudes?

Answer 4

Transformer

Question 5

Which type of patterns are plotted on graph paper that result from changes in amplitude with respect to time?

Answer 5

Waveform

Question 6

What is the most commonly used means for producing or using electricity?

Answer 6

Magnetism

Question 7

What year did Hans Christian Oersted discover a definite relationship between magnetism and electricity?

Answer 7

1819

Question 8

Which conductor rule can the relation between the direction of the magnetic lines of force around a conductor and the direction of electron current flow in the conductor be determined?

Answer 8

Left-Hand rule

Question 9

Which unit indicates one cycle per second?

Answer 9

Hertz (Hz)

Question 10

What is the number of complete cycles of alternating current or voltage completed each second referred to as?

Answer 10

Frequency

Question 11

What is frequency always measured and expressed in?

Answer 11

Hertz

Question 12

What is the time required to complete one cycle of a waveform called?

Answer 12

Period

Question 13

What is the distance from zero to the maximum value of each alternation called?

Answer 13

Amplitude

Question 14

What is the distance along the waveform from one point to the same point on the next cycle called?

Answer 14

Wavelength

Question 15

How many maximum or AC peak values during each complete cycle of AC are there?

Answer 15

Two

Question 16

What are alternating voltage and current usually expressed in?

Answer 16

Effective values

Question 17

Which alternating voltage or current value is the value of voltage or current at one particular instant?

Answer 17

Instantaneous

Question 18

What is the value of alternating voltage or current that will have the same effect on a resistance as a comparable value of direct voltage or current will have on the same resistance?

Answer 18

Effective

Question 19

Which method is the rate at which heat is produced in a resistance form a convenient basis for establishing an effective value of alternating current known as?

Answer 19

Heating effect

Question 20

Which law states that current is directly proportional to the applied voltage?

Answer 20

Ohms law

Question 21

What are two sine waves that are precisely in step with one another said to be?

Answer 21

In phase

Question 22

What is the amount by which one sine wave leads or lags another sine wave measured in?

Answer 22

Degrees

Question 23

Which type of elements are resistors, lamps, and heating elements examples of?

Answer 23

Resistive

Question 24

What is formed by wire wound around a core?

Answer 24

Coil

Question 25

What is the effect called when a conductor is in a magnetic field and either the field or the conductor moves, an emf (voltage) is induced in the conductor?

Answer 25

Magnetic induction

Question 26

What is the maximum value reached during one alternation of a sine wave called?

Answer 26

Peak Value

Question 27

The average value of a sine wave of voltage or current is the average of all the instantaneous values during one alternation. The average value is equal to what amount of the peak value?

Answer 27

0.636

Question 28

How many times the peak value is the effective value of a sine wave?

Answer 28

0.707