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electrical theory [finalized!] > [D2L] Final Review > Flashcards

[D2L] Final Review Flashcards

1
Q

What is the term for electrical charge at rest?

A

Electrostatic

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2
Q

What is required to form a magnetic domain (all atoms become aligned resulting in magnetism in one direction)?

A

Magnetic moments

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3
Q

How many electrons in a coulomb

A

6.28 x 10 exponent 18

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4
Q

one volt is the value of the difference in charge that will cause a current of one ampere to flow in a circuit with a resistance of one ohm

A

True

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5
Q

What affects the ability of a conductor to transmit an electrical current?

a) Cross-sectional area
b) Length
c) Diameter
d) All of the above

A

All of the above

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6
Q

What are the 4 components of a practical electrical circuit? (what is required for a proper circuit)

A

Source of emf, conductors, switch, load

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7
Q

To calculate the Emax value of a sine wave, Divide the RMS value by the ( ) or Multiply RMS by ( ).

A

Sine of 45°, √2 (square root 2)

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8
Q

Determine the instantaneous voltage at 30° if an ac voltmeter reads 110v

A

78v
(AC voltmeter = RMS)

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9
Q

Which of the statements are true?

a) Voltage has the same charge between two points
b) Voltage is measured across a device, between two separate points along two different conductors
c) Voltage can be defined as a balance of electron distribution
d) Voltage is the measurement of difference in charge between 2 poles

A

Voltage is the measurement of difference in charge between 2 poles

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10
Q

An (emf) electromotive force maintains the difference in charge

A

True

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11
Q

What is the symbol for electrical Charge?

A

Q

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12
Q

There are six methods for producing an emf. Pick 2 source names that ARE NOT methods. (MULTISELECT)

a) Light
b) Heat
c) Electrical
d) Pressure
e) Radiant
f) Chemical

A

Electrical
Radiant

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13
Q

Using a “CAT-l” electrical meter device, you can test utility connections and power lines?

A

False, CAT 3 & 4

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14
Q

Which one is incorrect?

a) Never use an ohmmeter on a energized circuit.

b) Clamp around only one wire when using an ammeter

c) If the display meter is flashing on and off, the measurement is greater than the range overload setting on the meter

d) When checking polarity on an AC circuit, Red goes to hot, Black goes to Negative

A

When checking polarity on an AC circuit, Red goes to hot, Black goes to Negative

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15
Q

In an Capacitive circuit, Current leads Voltage by 90 degrees?

A

True (ICE)

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16
Q

????If the instantaneous voltage is 10V at 110 degrees, what would voltmeter read?

A

7.937

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17
Q

A lock that you use to lock out equipment can have more then one key?

A

False, only one

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18
Q

what amount of electrical current can cause heart failure or death?

A

100mA to 200mA

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19
Q

A Transformer is a…..

A

Series of windings used to step up/down voltage

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20
Q

Inductance is the opposition of

A

Change in Current

21
Q

what is the positive plate called on a battery? (hint: the negative plate has an “n” in the word”)

A

Cathode (Positive)

Anode (Negative)

22
Q

Thermocouples use heat to generate Electricity?

A

True

23
Q

What is Faraday’s law?

A

States that the magnitude of an induced voltage of a conductor is proportional to the rate that it cuts the lines of flux from a magnet.

24
Q

A conductor moving parallel to lines of magnetic forces produce:

A

Minimum emf

25
Q

what does increasing the current in a coil do to the EMF

A

increase the EMF

26
Q

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

A

True

27
Q

Gas burners can have built-in _______ ignition system. (think BBQ)

A

piezo-based

28
Q

What is the order of the 7 steps normally used in a lockout procedure? (Drop down selection)

A
  1. Notification
  2. Shutdown
  3. System Shutdown
  4. Lockout
  5. Tag
  6. Recheck
  7. Re-energize
29
Q

What are the steps for preforming an operational test of an ohm meter before you check for a voltage in an unknown circuit? (Multi select)

a) Check meter to a known voltage
b) Check the circuit
c) If it shows de-energized, check meter to a known voltage source again
d) Check polarity of circuit
e) Make sure the power source is on and stable

A

a) Check meter to a known voltage
b) Check the circuit
c) If it shows de-energized, check meter to a known voltage source again

30
Q

If the amperage reading is lower then your clamp-on ammeter’s capability, you can loop the single conductor through the clamp to take a reading.

A

True

31
Q

Polarity is NOT a factor when using an ohmmeter.

A

True

32
Q

Polarity is NOT important when measuring ac currents.

A

True

33
Q

which of the following factors determine the extent of injury a current will have on the body? (Multi select, pick 4)

a) A persons skin resistance
b) Improper grounding
c) Size of the area of contact
d) Which part of the body is in contact
e) puddles on the ground
f) how much pressure is applied

A

a) A persons skin resistance
c) Size of the area of contact
d) Which part of the body is in contact
f) how much pressure is applied

34
Q

what is the voltage rating for Class 0 (red) electrical rubber gloves?

A

up to 1,000 V

35
Q

One alternation occurs within 180 degrees of an electrical sine wave

A

True, 360 is a cycle

36
Q

The time required for one alternation to complete is also known as a period.

A

False

37
Q

One cycle is one positive alternation and one negative alternation

A

True

38
Q

When a 4 pole alternator turns 1500r/min the output frequency is 60hz

A

False, it’s 50Hz

39
Q

Three phase wires are White, Black, and Blue?

T or F

A

False

Phase A: black
Phase B: red
Phase C: blue

40
Q

Fuse rating can not be greater than 125% of the smallest wire or component in the circuit

A

True

41
Q

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

A

True

42
Q

Arc flash can be caused by environmental, aging material and worker interaction. Which of these is not a likely concern

a) Condensation
b) Dust on circuits
c) Resetting a circuit breaker
d) Current in mA

A

Current in mA

43
Q

Fuses allow 3x their rated current for a few seconds for surging of motors

A

True

44
Q

What is flux density?

A

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

45
Q

What are some examples of Ferromagnetic materials? (MULTI-SELECT)

Iron

Wood

Nickel

Cobalt

Glass

A

Iron
Nickel
Glass

46
Q

What pole do flux lines leave and then enter?

A

Leave through the north and enter through the south

47
Q

What is a Megohmmeter (Meggar) used for?

A

Checking Wire Insulation

48
Q

If a wire is shorted out
If a wire is burnt open

A

Just think of it as an open switch(not there)
not functionable, no current can flow

49
Q

GFCI(Ground Fault Circuit Interrupter) detects leakage as low as 3-5mA (0.003-0.005A)

A

True

electrical theory [finalized!] (18 decks)

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