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Electrical Foundations (Occupational Core) > Line E > Flashcards

Line E Flashcards

1
Q

Devices designed to change other forms of energy into electrical energy are referred to as __________ of electricity

A

Sources

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2
Q

List six methods of producing electricity

A 
Friction
chemical 
pressure
heat
light
magnetism
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3
Q

The term triboelectric effect refers to the generation of electricity by _________?

A

Friction

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4
Q

The term piezoelectric effect refers to the generation of electricity by ________?

A

Pressure

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5
Q

the device used to produce electricity by heating a junction of two dissimilar metals is referred to as a _______?

A

Thermocouple

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6
Q

The device that generates electricity from the sun energy is called an ?

A

Photovoltaic cell

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7
Q

The work-per-unit-charge done by a source on the electric charges, to move them against the electric field , is referred to as _________________?

A

Electromotive forces

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8
Q

Most of the electrical energy used in your home is produced by _________?

A

Magnetoelectric effect

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9
Q

State the law of conservation of energy

A

Energy can be neither created nor destroyed

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10
Q

The solar cell in a simple calculator is called a _________?

A

Photovoltaic cell

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11
Q

The Charge on 6.24 x 10(small 18) electrons is referred to as a _________?

A

Coulomb

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12
Q

If 4 coulombs of charge pass a given point in a conductor over a period of 2 seconds, current is flowing at the rate of ______ Amperes

A

2

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13
Q

If 3600 joules of work are required to move 6 coulombs of a charge from point A to point B, the potential difference between the two points is _____ volts

A

600

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14
Q

The term used to represent the opposition to current flow in a electric circuit is _______?

A

Resistance

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15
Q

What is the quantity symbol, electrical unit, and unit abbreviation for “Charge”?

A

Q, coulomb, C

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16
Q

What is the electrical quantity, electrical unit, and unit abbreviation for “P”?

A

Power, watt, W

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17
Q

What is the electrical quantity, quantity symbol, and unit abbreviation for “ohm”?

A

Resistance, R, omega (horseshoe shaped)

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18
Q

What is the quantity symbol, electrical unit, and unit abbreviation for “emf or PD”?

A

E, volt, V

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19
Q

What is the electrical quantity, quantity symbol, and electrical unit for “A”?

A

Current, I, ampere

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20
Q

The product of emf, current, and time is ______

A

energy

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21
Q

The product of emf and current is ______

A

power

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22
Q

The product of power and time is ______

A

energy

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23
Q

How many kilowatt hours of energy does it require to operate a 1200 watt hair dryer for 10 minutes?

A

0.2 kW/h

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24
Q

If a 1200 watt hair dryer is ran for 10 minutes, what is the cost of operation if the supply authority charges $.07 per kilowatt hour?

A

$.014

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25
Q

If a 25 kW electric furnace operates for 3 hours in a 24-hour period, and the supply authority charges $.07/kW/h, what does it cost each day to operate the furnace?

A

$5.25

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26
Q

If an electric clothes dryer draws 30 A at 240 V and is operated for 45 minutes, what is the kW/h consumption?

A

5.4 kW/h

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27
Q

What is the power rating of an electric clothes dryer that draws 30 A at 240 V and is operated for 45 minutes?

A

7.2 kW

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28
Q

A 1500 W/240 V base board heater is operated for 15 minutes and a 1200 W/120 V baseboard heater is operated for 30 minutes.

1) What is the combined kW/h consumption of the two heaters?
2) At $0.07/kW/h, what is the cost of operating the two heaters?

A

1) 0.975 kW/h

2) $0.068

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29
Q

LED is a short name for a solid state device actually called a:

1) levitating-energy device.
2) light-exciting dipole.
3) light-energized diode.
4) light-emitting diode.

A

light-emitting diode.

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30
Q

The reacting cylinder part of a dry cell is often made of:

1) zinc.
2) carbon.
3) magnesium.
4) cardboard.

A

zinc.

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31
Q

The main disadvantage of mercury lamps and sodium vapour bulbs is that they:

1) cannot be used outside.
2) are less efficient than incandescent bulbs.
3) produce acceptable levels of heat.
4) produce an “unnatural” light.

A

produce an “unnatural” light.

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32
Q

Silver plating is an example of:

1) thermocoupling.
2) electrolysis.
3) an electrode.
4) electrical refining.

A

electrolysis.

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33
Q

The major advantage of a secondary cell over the dry cell is that the secondary cell:

1) can be used in wet weather.
2) takes up less room.
3) is fully rechargeable.
4) produces direct current.

A

is fully rechargeable.

34
Q

LED is a solid state device used for:

1) home lighting systems.
2) numerical displays.
3) sensors.
4) all of the above.

A

all of the above.

35
Q

The electrolyte in a dry cell is:

1) dry powder.
2) carbon and zinc.
3) a moist paste.
4) diluted sulfuric acid.

A

a moist paste.

36
Q

One common way to convert chemical energy into electrical energy is to use a:

1) generator.
2) solar cell.
3) secondary cell.
4) diode.

A

secondary cell.

37
Q

The metal strips in primary and secondary cells are called:

1) electrolytes.
2) carbon rods.
3) extrusions.
4) electrodes.

A

electrodes.

38
Q

The Law of the Conservation of Energy says energy:

1) is easy to make.
2) can only be changed in form.
3) cannot change form.
4) can be destroyed.

A

can only be changed in form.

39
Q

When the current is reversed in a car battery:

1) nothing happens.
2) the chemical process also reverses.
3) the battery polarity changes.
4) the electrodes melt.

A

the chemical process also reverses.

40
Q

In secondary cells, dilute sulfuric acid is often used as the:

1) electrolyte.
2) electrode.
3) charging fluid.
4) electrolysis.

A

electrolyte.

41
Q

One common way to convert chemical energy into electrical energy is to use a:

A)generator.

B)solar cell.

C)secondary cell.

D)diode.

A

Secondary Cell

42
Q

The incandescent bulb is considered a rather inefficient light source because it:

1) is fragile and breaks easily.
2) produces too much heat.
3) produces a poor quality of light.
4) is expensive to manufacture.

A

produces too much heat.

43
Q

Photovoltaic cells convert electrical energy from the energy of:

1) mechanical movement.
2) chemicals.
3) heat.
4) light.

A

light.

44
Q

The role of the turbine is to convert:

potential energy to kinetic energy.

kinetic energy to mechanical energy.

mechanical energy to electrical energy.

electrical energy to heat energy.

A

kinetic energy to mechanical energy.

45
Q

Which of the following methods of generating electrical energy is most commonly used in BC?

steam plants

atomic electrical plants

hydroelectric plants

internal combustion engine plants

A

hydroelectric plants

46
Q

Which type of current is generally produced by hydroelectric generation?

single-phase direct

three-phase direct

single-phase alternating

three-phase alternating

A

three-phase alternating

47
Q

Which component in hydroelectric energy generation controls the RPM of the generator?

buss bar

governor

tailrace

penstock

A

governor

48
Q

The output voltage from the generators at the Revelstoke dam is:

16,000 V.

30,000 V.

60,000 V.

100,000 V.

A

16,000 V.

49
Q

Which of the following is the prime mover in hydroelectric generation?

penstock

generator

spillway

turbine

A

turbine

50
Q

What is the role of penstocks in a hydroelectric dam?

to control the flow of water propelling the turbine

to channel the falling water to the turbine

to direct overflow during high water

to connect the turbine to the generator

A

to channel the falling water to the turbine

51
Q

An electric drill converts electrical energy into:

light energy.

kinetic energy.

mechanical energy.

triboelectricity.

A

mechanical energy.

52
Q

What is the function of the spillway chute?

to release high waters in spring run-off

to direct falling water to the turbine

to convert mechanical energy to electrical energy

to control the rotation of the generator

A

to release high waters in spring run-off

53
Q

The primary disadvantage of high voltage transmission is:

loss due to leakage.

a reduction in amperage.

increased conductor costs.

a reduction in transmission speed.

A

loss due to leakage.

54
Q

Which instrument is used to meter users’ consumption of electrical energy?

watt meter

kilowatt/volt meter

kilowatt/hour meter

kilovolt/hour meter

A

kilowatt/hour meter

55
Q

Why is it necessary to step up alternator voltage prior to long distance transmission?

to increase amperage

to supply industrial loads

to increase speed of transmission

to save on conductor costs

A

to save on conductor costs

56
Q

Within the generator, energy is converted from:

kinetic to electrical energy.

mechanical to electrical energy.

electrical to mechanical energy.

kinetic to mechanical energy.

A

mechanical to electrical energy.

57
Q

Residential consumers are most often supplied with a:

120/240 V system.

120/277 V system.

220/480 V system.

480/600 V system.

A

120/240 V system.

58
Q

The “head” is defined as:

the amount of kinetic energy available for conversion to mechanical energy.

the amount of mechanical energy available for conversion to electrical energy.

the difference in elevation between the reservoir and the tailrace water level.

the efficiency of the conversion between states of energy.

A

the difference in elevation between the reservoir and the tailrace water level.

59
Q

The relationship between watts and horsepower is expressed by:

A)1 hp = 1000 W.

B)7.46 hp = 1 W.

C)1 hp = 746 W.

D)1 hp = 9.81 W.

A

1hp = 746 W

60
Q

The horsepower needed to lift a mass of 25 kg, 2 m in 2.5 seconds is about:

A)0.131 hp.

B)0.263 hp.

C)2.63 hp.

D)26.3 hp.

A

0.263 hp

61
Q

A 1500 W kettle takes 8 min. to boil water. The energy costs $0.05/kWh. The cost of boiling the water is:

A)$0.001.

B)$0.01.

C)$0.10.

D)$1.00.

A

$0.01

62
Q

Electrical energy is usually sold by the:

A)joule.

B)watt.

C)watt-hour.

D)kilowatt-hour.

A

Kilowatt-hour

63
Q

The correct relationship for work, force and distance is expressed in the equation:

A) w = F x d.

B) w = F /d.

C) w = d / F.

D) w = F2 x d.

A

W= F x D

64
Q

A 240 V elevator motor drawing 10 A lifts 300 kg, 30 m in 60 sec.
The power out (Pout) would be:

A) 24.5 W.

B) 1471.5 W.

C) 2400 W.

D) 5886 W.

A

1471.5 W

65
Q

A mass in kg can be mathematically changed into a force by:

A) multiplying the kg by 746.

B) multiplying the kg by 4186.

C) multiplying the kg by 9.81.

D) dividing the kg by 9.81.

A

Multiplying the kg by 9.81

66
Q

Given that a meter read 5908 kwh’s in Nov. and 8332 kwh’s in Dec. and given the cost for energy is $0.05/kWh, the bill received in December will be:

A) $12.12.

B) $41.66.

C) $121.20.

D) $416.60

A

$121.20

67
Q

A single kilowatt is the same as (that is, 1 kW =___________).

one horsepower (1 hp)

one hundred watts (100 W)

one thousand watts (1000 W)

one Newton-meter (1 Nm)

A

one thousand watts 1000 W

68
Q 
A 240 V elevator motor drawing 10 A lifts 300 kg, 30 m in 60 sec.
The power (Pin) would be:

A) 24 W.

B) 576 kW.

C) 2400 W.

D) 24,000 W.

A

2400 W

69
Q

A common unit of power is the:

A) Newton.

B) Newton-meter.

C) joule.

D) watt.

A

Watt

70
Q

Most artificial light in office buildings is provided by:

incandescent bulbs.

sodium vapour bulbs

fluorescent tubes.

mercury arc lamps.

A

fluorescent tubes.

71
Q

A 240 V elevator motor drawing 10 A lifts 300 kg, 30 m in 60 sec.
The work done in raising the 300 kg is:
Question 11 options:

A) 98.1 J.

B) 98.1 Nm.

C) 88,290 J.

D) 1471.5 W.

A

88,290 J

72
Q

Power, work and time are correctly related in the equation?

1) P = w / t(seconds)
2) P = t(seconds) x w
3) P = J / t(hours)
4) P = J x t(hours)

A

P = w / t(seconds)

73
Q

A 240 V elevator motor drawing 10 A lifts 300 kg, 30 m in 60 sec.
What is the efficiency of the motor?

A

61.3%

74
Q

1 kcal is equal to how many Joules (per kg of water)?

A

4186 J

75
Q

A hot water tank contains 200L of water having a temperature of 10oC. You wish to raise the temperature to 60oC. The hot water tank has a 3000W heating element. Electrical energy costs $0.05/kWh. Calculate the cost of heating the tank of water.

A

$0.58

76
Q

What energy would be required to raise the temperature of 10L of water from 25oC to 40oC?

A

627900 J

77
Q

How long would a 4.5kW heater take to produce 230000J?

A

51.1 seconds

78
Q

Calculate the efficiency of 14hp gas driven generator that produces 42A at 145V.

A

58.3%

79
Q

What is the input wattage of a 20hp motor with an efficiency of 71.2%?

A

20955 W

80
Q

How many kWh s were used if the cost was $144.60 and the rate for electricity was $0.06/kWh?

A

2410 kWh

Electrical Foundations (Occupational Core) (4 decks)

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