Brainscape's Knowledge GenomeTM

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


See full index

Lighting > Lighting > Flashcards

Lighting Flashcards

1
Q

Luminous efficacy

A

How well a light source produces visible light.

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

Luminous efficacy of incandescence/ LED / low pressure sodium

A

Incandescent = 22Lm (worst)
Low pressure sodium 200 (best
LED = 150 lumins

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

Two types of light measurments

A

1: The total quantity of light output (lumin)
2: the quality of light (Lux)

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

Explain luminous flux

A

The quantity of light output from source. Measured in lumen (Lm)

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

Explain flux density

A

The density of light flux measured on a surface. Measured in lux (Lx)

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

Two lighting equations

A

1:Inverse square law
2:Cosine law of incidence

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

Explain inverse square law

A

Illumination is inversely proportional to the square distance between source and surface. Light gets dimmer further away you go in distance

E = I/d2

E = lux
I= light intensity
D= distance squared

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

Explain cosine law

A

E = I/d2 x cos

Illumination changes with angle change

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

Lux = intensity in lumens/distance in metre squared meaning?

A

Double the distance from light source means 1/4 of the illumination on surface

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

Lumen

A

Amount of visible light seen from a source

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

Lumen

A

Amount of visible light seen from a source

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

What are luminaries

A

Complete light fixture ( housing, ballast, wiring etc)

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

Two types of light loss

A

1: lumen depreciation (bulb deteriorates over time and gets less intense the older)

2: luminaire dirt depreciation
(The accumulation of dirt can cause loss of 30% or more) can be avoided by ventilation or cleaning

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

What part of eye does light enter

A

Cornea

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

Light passed through _______ and then strikes the ______ to form optical image

A

Passes through LENS and strikes RETINA

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

What two nerves does retina contain

A

Rods: provides sensitivity to light

Cones: allows us to see detail and colour

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

4 Factors affecting vision

A

1: size ( larger object easier to see)
2: brightness
3: contrast ( different brightness)
4: time ( longer visible more detail seen)

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

What wavelength can human eye detect

A

Between 380nm - 760 nm

Nm= nano metres

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

Most sensitive wavelength for human eye

A

555nm (yellow / green)

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

What are the 3 primary colours

A

Green red and blue

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

What is another word for colour temperature

A

Chromaticity

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

What is colour temperature measured in?

A

Degree Kelvin (k)

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

What is a low temp measured at?

A

Bellow 3000k lower kelvin = warmer colour (yellow/red)

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

What is high temp measured above in kelvin?

A

Above 4000k = cool colour

Higher k = whiter light (blue / white )

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

Explain CRI

A

Colour rendering index:

a measurement of how natural colors render under an artificial white light source when compared with sunlight. The index is measured from 0-100, with a perfect 100 indicating that colors of objects under the light source appear the same as they would under natural sunlight.

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

Does high CRI mean less or more colour distortion

A

Higher the CRI = the less distorted and more like what we would see under natural sunlight

27
Q

Rated life of lamp is determined by what?

A

By 50% lamp failures under normal conditions

28
Q

Advantages of incandescent light

A

Cheaper
Colour appears more natural

29
Q

What is incandescent filament lights made of

A

Tungsten as has a 3419c melting temperature

30
Q

Higher filament temp = lifespan reduced or increased?

A

Reduced - a 100w lightbulb at 120v will
Burn dimmer than the same lightbulb at 130v. Will have longer lifespan at 120v

31
Q

Lower filament temp means?

A

Less light produced but longer lifespan

32
Q

What gas is in an incandescent and why?

A

Inert gas (argon) it is used to stop evaporation of tungsten filament when it gets hot

33
Q

Incandescent have a positive temp coefficient why?

A

When cold draws more amps. When it warms up resistance increases and less amps flow

34
Q

What does code and number mean on bulbs

A

Letter = shape/style of bulb
Number = diameter of face of bulb in inches 1/8th inch

35
Q

Describe inrush current and why does it blow out bulbs

A

A surge of current when switching light on as the cold resistance is very minimal allows a lot of current to pass. Up to 20x more amps flow

36
Q

What are tungsten halogen lamps

A

1:Made of quartz as quartz can withstand high temp.

2:Burns very hot and bright ex. Car headlight/spotlight/floodlights

3: cannot touch with bare hands as oil on skin damage quartz surface

37
Q

What is lifespan of tungsten halogen lamps

A

2500-3000 hours usually MR16 12volts and 10-50watts

38
Q

Advantages of LED Lights

A

1: low power consumption
2: no early installation failures
3: resistant to shock and vibration
4: instant start (no warming up)
5:lifespan of 50,000 hours

39
Q

Disadvantage of LED

A

1:More expensive
2:heat sensitive excess heat effects lifespan
3:not all dimmable
4:good CRI but not as good as incandescent

40
Q

Grounded conductor =

A

Neutral

41
Q

Ungrounded conductor =

A

Hot (black or red)

42
Q

What is efficacy

A

Light Source efficiency in turning electrical energy into light energy= led more efficient lower watt and more light

43
Q

What are mogul bases used for

A

Wattage over 300w or higher

44
Q

Screw shell MUST be attached to neutral- true or false

A

True

45
Q

What is the most common base used for lights

A

Edison screw base

46
Q

Most used lamp sizes

A

Candelabra, intermediate, medium , mogul

47
Q

What plans are used commonly in Electrical construction prints to show the power distribution

A

Single line drawings

48
Q

Single line only shows supply side no load. True or false

A

True- only supply on top line

49
Q

Riser diagrams are used more than any other in electrical construction

A

True

50
Q

How many views in orthographic projection (max)

A

Max of 6 views. Usually 3 top,front,side

51
Q

Orthographic projections are drawn to scale. T-F

A

True

52
Q

What is most common use for orthographic projections in electrical

A

Machines and equipment in from of detail and assembly drawings

53
Q

Min rated wiring temperature

A

90degree nmd90

54
Q

To prevent induction heating - all conductors of same circuit must be in same raceway t/f

A

True. Must be in same metal raceway

55
Q

Max voltage to code CEC

A

150v and must use #8-32 machine screw

56
Q

Lamp life / output. Lamp life is inversely proportional to voltage. T/f

A

True

57
Q

Power light output is proportional to voltage t/f

A

True

58
Q

1 watt = how many lumen

A

683

59
Q

Melting point of tungsten and quartz

A

3500c tungsten
1700c quartz

60
Q

Switch/relay will operate EXTRA LOW VOLTAGE 24V or less T/F

A

True

61
Q

What screws are used in lighting box

A

8 - 32 screws

62
Q

What is used in fluorescent lighting tube to assist current flow

A

Argon gas

63
Q

What is used to transform uv into visible light

A

Phosphor coating

Lighting (1 decks)

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