Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Electrical Theory [FINALIZED!] > [D2L] Final Exam > Flashcards

[D2L] Final Exam Flashcards

1
Q

If we are checking ohms on a normally closed switch when the 120v system is energized and the ohm meter is flashing OL, what is happening?

A

Silly apprentice, turn the power off or check with the meter turned to voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Soft Iron has

A

High permeability and low reluctance to magnetic flux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does it mean if your meter is reading a negative number?

A

the meter is connected in reverse polarity to the DC circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The effect that current has on a human body depends on four factors, which of these are NOT one of those factors

Area of contact
Pressure of contact
Improper grounding
Skin resistance

A

Improper grounding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many current paths are there in a parallel circuit?

A

more than 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

DC transformers are commonly used to drop high voltage to low voltage?

A

False, Transformers only work with alternating current (AC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

an alternator converts…………………, into…………………… energy

A

mechanical, electrical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What would the total current be in a circuit with a 20vdc power source and a total resistance of 43ohms

A

0.47 A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What would the total resistance in a circuit be if there were 6.2 amps flowing from a 41 vdc power supply?

A

6.61 ohms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What would the power supply voltage be of a 47ohm circuit drawing 6.70 amps?

A

315 V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which of the following is NOT a method of producing emf?

A

Radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Kirchhoff’s current law states:

A

All current values entering a junction point must equal all current values exiting the junction point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Three factors which contribute to impedance are

A

Resistance, inductive reactance and capacitive reactance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

increasing the flow of current through a coil will..

A

increase the strength of the magnetic field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is inductance defined?

A

The characteristic of an electric circuit that opposes a change in Current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

In circuits with primarily capacitive loads, current leads the voltage

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The CSA Z462 specifies workplace electrical safety

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is voltage drop?

A

When current flows through any conductor, there is a reduction in the EMF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the unit of measurement for a Charge?

A

Coulomb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Electron flow in a circuit travels from positive to negative

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

A Category II (CAT II) meter is safe to use on RACM equipment

T or F

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Megohmmeters generate high voltage, low current signals to test insulation resistance. For test voltages at 500 VDC the minimum insulation resistance is ____

A

1 MO (megohms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

A conductor moving parallel to lines of magnetic force produces:

A

Minimum EMF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

if the RPM of an alternator increases, then the output frequency of the alternator

A

Increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What electrical charge is the basis for a precipitation-type of air filter?

A

electrostatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which of the following are required to form a magnetic domain?

A

magnetic moments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Inductance is the property of an electrical circuit where a current change forces the rise of a voltage flowing in the reverse direction of the incoming voltage

T or F

A

True

28
Q

What is the positive plate called on a battery?

A

Cathode

29
Q

The number of turns on the primary and secondary coils determines the amount of the mutually induced secondary coil voltage.

A

True

30
Q

Which source of EMF is at work when you plug your radio into a wall receptacle?

A

Magnetic

31
Q

Single conductors may have a Max load of 80% of the rated 15A

T or F

A

True

32
Q

What is flux density?

A

The number of lines of force passing through a unit area of material

33
Q

the emf that is induced in a circuit by electromagnetism, is proportional to the rate of change of flux linkage. this statement could be used to summarize?

A

faraday’s law

34
Q

What amount of current is enough to kill a person?

A

100 to 200 mA

35
Q

Current measurement is in Amperes how many mA are in one A?

A

1,000

36
Q

What is the main purpose of a lockout system while working on electrical systems?

A

To prevent equipment from being energized while someone is working on it.

37
Q

What is electromagnetism?

A

The interaction of the forces that electric fields and magnetic fields create

38
Q

How is alternating current generated?

A

By moving wires through a magnetic field.

39
Q

When any force squeezes a crystals made from bone, wood, metal or minerals the material compresses and produces electricity, this is called…

A

Piezoelectricity

40
Q

what is the FIRST thing that must be done if an electrical shock occurs?

A

remove the victim

41
Q

when illuminated, an incandescent light bulb will have a magnetic field close to the filament (glowing coil)?

T or F

A

True

42
Q

An averaging meter is the same as an RMS Meter

T or F

A

False

43
Q

ferromagnetic materials, like iron, allow magnetic flux to pass through them easily because they have a high

A

permeability

44
Q

Soft Iron has a low reluctance which will concentrate magnetic flux more easily than air

T or F

A

True

45
Q

A capacitor has negatively and positively charged sections separated by a

A

Dielectric

46
Q

An ECM motor stands for electronically commutated motor

A

True

47
Q

According to the left hand conductor rule, when your thumb is up, the…….

A

electrons travel the direction your thumb is pointing, with a rotating magnetic field pointing in the direction of your fingers around it

48
Q

Which metric is most accurate to prove work is actually being done

Voltage detected at the load
Amp draw is detected at the load

A

Amp draw is detected at the load

49
Q

What is the vdc power source of a 2.0 amp series circuit with a 9, 4, 6, 10 ohm resistors

A

58 V

50
Q

What is the current of a 120 vdc series circuit with a 7, 10, 8, 8 ohm resistors

A

3.64 A

51
Q

Yesterday you were repairing a 210 vdc power source of a 2.0 amp series circuit, when you returned this morning you found one of your 5 resistors was burned beyond recognition. Calculate the missing resistor if you were left with a 15.0, 7.0, 11.0, 12.0 ohm resistors.

A

60 ohms

52
Q

Using heat to produce electricity is the process known as

A

Seebeck Effect

53
Q

if Emax is 120V what is the instantaneous value at 60*?

A

103.92 vac

54
Q

what would the instantaneous voltage value be at 30* angle of the sine wave of a system with 169.7V Peak voltage

A

85 vac

55
Q

What frequency of ac power is being generated from an alternator spinning at 3600rpm with 2 poles?

A

60 hz

56
Q

What is the rpm of a 120vac 36 hz. motor with 4 poles?

A

1080 rpm

57
Q

What is the maximum peak voltage of a 224 vac rms power system?

A

317 v

58
Q

What is the effective voltage of a sine wave that peaks at 130 vac?

A

92 v

59
Q

A 4 pole alternator rotates 3 times, producing how many electrical degrees?

A

2160

60
Q

What are two classifications of Magnets?

A

Temporary and Permanent

61
Q

What is the unit of measurement for inductance?

A

Henry (H)

62
Q

360° in an electrical sine wave is also known as what?

A

a cycle

63
Q

one of the 3 factors that determine the severity of an arc flash is

A

the time it takes the circuit breaker to open

64
Q

which of these are not likely to significantly increase the probability of an arc flash?

A

LED lights

65
Q

What do you read with your voltmeter?

A

Effective value

66
Q

What happens if there is a loose or poorly made electrical connection?

A drop in amperage
A drop in resistance
A drop in voltage

A

A drop in voltage

Electrical Theory [FINALIZED!] (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions