Lighting Flashcards
1
Q
Transparent outer membrane surrounding the eye
A
Cornea
2
Q
Two types of optic nerve receptors in the retina
A
Rods and cones
3
Q
What is the purpose of the rods
A
Provide sensitivity to brightness, allowing us to see low levels of light
4
Q
What is the purpose of the cones
A
Allow us to perceive finer details and distinguish colours
5
Q
What are the factors affecting visibility?
A
Size, brightness, contrast, time
6
Q
What is the range of wavelength visible light?
A
380-760 nanometers
7
Q
What is the wavelength most visible to the human eye?
A
555 nanometers
8
Q
Light is a special form of _________
A
Electromagnetic radiation
9
Q
Term used to describe colour of light source
A
Colour temperature (chromaticity)
10
Q
What is CRI?
A
Colour rendering index. Expresses the ability of a light source to portray the colour appearance of objects accurately when compared to a standard light source f the same colour temperature
11
Q
Where are regular fluorescent lamps on the CRI?
A
Good/fair
12
Q
Where are deluxe fluorescent lamps on the CRI?
A
Excellent/good
13
Q
Where are incandescent lamps on the CRI?
A
Excellent. The top. CRI of 97.
14
Q
Where are metal halides (400w) on the CRI?
A
Good.
15
Q
Where are mercury Vapor’s on the CRI?
A
Poor
16
Q
Where are HPS on the CRI?
A
Poor
17
Q
Where are LPS on the CRI?
A
Very bottom. Undefined. Terrible.
18
Q
Where are mercury Vapor lamps on the CRI?
A
Bottom. Poor.
19
Q
Sort metal halide, LPS, HPS, mercury Vapor in the CRI.
A
Metal halide, HPS (deluxe), mercury Vapor (coated), HPS (diffuse coated), mercury Vapor (clear), LPS
20
Q
Two fundamental measurements of light
A
Quantity, quality
21
Q
The term for quantity of life and it’s unit
A
Luminous flux. Lumens.
22
Q
The difference between luminous intensity and illuminance.
A
Luminous intensity: light emitted towards a specific direction within a given angle.
Illuminance: amount of light falling on 1m^2
23
Q
What is efficacy?
A
Ratio of light output (lumens) compared to power input (watts) for a light source
24
Q
1 watt produces _____ lumens
A
683
25
Two types of incandescent lamps
Carbon and Tungsten filament
26
Three factors contributing to quality of light.
Glare, diffusion, color.
27
Difference between a luminaire and lamp
Luminaire is the entire fixture including wiring and ballast, lamp is the bulb
28
The purpose of a luminaire
To provide an appropriate amount of light
29
Name the five classes of luminaires
Direct, indirect, semi indirect, semi direct, direct indirect
30
What type of lamps have a restrike time of 4-6 minutes?
Mercury Vapor
31
What type of lamp is this: passes current through a filament, heating it to glowing
Incandescent
32
What type of lamp is 5% useful energy and 95% heat loss?
Incandescent
33
What is the benefit of tungsten?
High melting point (over 3,000 degrees), and low rate of evaporation
34
About how many hours does an incandescent last?
1000
35
What bulb is code S?
Straight side. Looks like an Edison bulb.
36
What bulb is code F?
Flame. Looks like a flame.
37
What bulb is code G?
Globular. Round globe.
38
What bulb is code A?
Standard line. Think Standard A19’s
39
What bulb code is T?
Tubular. Fluorescent tube or cylinder bulb
40
What bulb is cide PS?
Pear shaped. Pear shaped standard
41
What bulb is code PAR?
Parabolic. Looks like the type in the bathroom vanity.
42
What bulb is code R?
Reflector. Larger parabolic, usually a flood light.
43
Bulbs 7.5w to 300w are ____ base
Medium
44
Bulbs 300w and larger are ____ base
Mogul
45
The two bases smaller than medium base.
Candelabra and intermediate.
46
Another name for the medium base.
Edison.
47
Low wattage and decorative bulbs usually have which type of base?
Candelabra or intermediate
48
What wattage are usually biposts?
500w or more
49
Do high or low wattage lamps have a higher efficacy?
High
50
T/F high filament temperatures produce greater efficacy
T
51
How do we slow the filament evaporation
40w and higher lamps are filled with inert gas
52
T/F tungsten halogen lamps provide a white light
True
53
What is the regenerative cycle?
The process preventing blackening on the inside of a lamp. Halogen gas.
54
How many hours do tungsten halogen lamps last?
2500-3000 hours
55
What wattage are usually tungsten halogen lamps?
300w, 500w, 1000w
56
Which lamps should you not touch?
Tungsten halogen
57
How does a mercury Vapor lamp work?
Current passes through argon gas and a tiny bit of mercury, argon heats up the mercury until it vaporizes,mercury vaporizes into the arc stream, arc intensity increases as lamp warms up, arc is the source of light
58
What light temperature is a MV?
About 6800 Kelvin, a blue light colour
59
Does a MV have a restrike time?
Yea. When turned on they have to warm up, gradually getting brighter, once turned off they need a cool down time before they turn back on. About 5-10 minutes.
60
Do HPS lamps have a restrike time?
No. They take about 5 minutes to warm up but they will turn on immediately with no restrike time.
61
How can you visibly tell a MV lamp?
Two electrodes, resistor, small tungsten wire, usually a long bar looking wire spanning the arc tube
62
Which lamps need a ballast?
Mercury Vapor, metal halide, fluorescent, LPS, HPS
63
What coating is on MVlamps?
Phosphor coating. Blocks UV. Helps make a beautiful yellow white colour.
64
What types of lamps are HIDs?
MV, metal halide, HPS
65
Metal halide fused quarts runs at ____ PSI
50
66
What is added to mercury Vapor in metal halide?
Halide salts. Gives it the white colour. About 4000 kalvin
67
How does a metal halide lamp work?
Arc starts through argon gas, discharge fills arc tube and glows a dim blue colour, mercury begins to vaporize, then heat begins to vaporize the halide salts. White coating on arc tube reflects heat back into arc tube to keep arc at specific temperature so halide salts stay vaporized.
68
Which is more efficient, metal halide or mercury Vapor?
Metal halide.
69
What is more efficient, metal halide or HPS?
HPS
70
When a metal halide is burnt horizontally instead of vertically, what happens to the life?
Halfs
71
The wavelength of visible light is called _____
Colour spectrum
72
Colour temperature of a light source is measured in _____ .
Kelvins.
73
What is the purpose of the CRI?
Express the ability of light to portray an objects true colours.
74
What are the four categories of the CRI?
Poor: 0-50
Fair: 50-60
Good: 60-75
Excellent: 75-100
75
The quantity of light output is measured in _____
Lumens. Luminous Flux.
76
What is the difference between luminous flux (Lumens) and luminous flux density (lux)
Lumens is the total light emitted by a light source. Lux is the light emitted towards a specific direction.
77
What is illuminance?
The amount of light falling on 1m2
78
What is luminance?
The light reflected to the eyes
79
What is luminous efficacy?
Ratio of light output to input.
Lumens to watts.
80
At 100% efficacy 1 watt =
683 lumens
81
How do incandescent bulbs work?
Passes electric current though a filament, heating it to an incandescent glow.
82
Why is tungsten used over carbon?
Tungsten has a higher melting point, and a low rate of evaporation.
83
What gas mixture is added to incandescent lamps? What is it called? What is it’s purpose?
Nitrogen and Argon.
Inert Gas
Reduce the rate of filament evaporation
84
High wattage lamps have _____ efficacy, _______ service life.
Higher efficacy, shorter service life.
85
Low wattage lamps have _____ efficacy, _______ service life.
Lower efficacy, longer service life.
86
What is the blackening on the inside of a bulb?
The tungsten evaporating.
87
What is the colour temp of a Tungsten Halogen?
Bright white about 6000 K
88
How long do incandescent and tungsten halogen lamps last?
Incandescent: 1000 hours
Tungsten halogen: 2500 - 3000 hours
89
What gases are found in tungsten halogen lamps?
Nitrogen and argon, and halogen
90
How does a tungsten halogen lamp work?
Halogen mixes with the evaporated tungsten from the filament, the tungsten halogen combo floats back to the filament where it is redepositrd onto the filament.
91
What is the purpose of the regenerative cycle?
To prevent the blackening in the inside of the bulb.
92
What is the purpose of the shape of the tungsten halogen?
The quartz has to get really hot for the regenerative cycle to work, so the bulb is thing to keep glass hot.
93
Can you dim a tungsten halogen?
Yes but not recommended because the quartz will not stay hot enough
94
What gases are in fluorescent bulbs?
Argon and a very small amount of mercury
95
How does a fluorescent work?
A ballast provides a high starting voltage, the high voltage ionizes the argon gas and current begins to flow. The resulting heat causes mercury to vaporize, the mercury and moving electrons through the tube produce UV radiation. The UV radiation produces a nice white light when it strikes the phosphor coating.
96
What is the most common ballast?
Rapid start. About 700-800V
97
What is the rated hours of a fluorescent lamp?
7500-20000 hours
98
What is a benefit of fluorescent lamps?
Produces very little heat and a lot of light. Very efficient.
99
What amperage do rapid start ballasts operate at?
430mA
100
What amperage’s do HO ballasts start at?
800mA
101
What are the two main functions of a ballast?
To provide a high starting voltage, and to keep current low after it is lit.
102
How long do ballasts last?
12-15 years
103
What is the most efficient lamp and it’s efficacy?
LPS, close to 200 l/w
104
What gases are found in LPS?
Argon, neon, metallic sodium
105
What are the benefits of an LPS?
Long life (18000 hours), instant restart no restrike time.
106
What temperature does sodium vaporize?
Between 240-300 degrees. Must stay above 300 to work.
107
What is the colour temperature of an LPS?
1800 K
108
How does an LPS work?
Ballast provides high striking voltage, the heat provides from startup gradually vaporizes the sodium, the neon gas at initial startup provides a dark red glow. As light output increases and sodium vaporizes it reaches full intensity of a yellow green glow.
109
How long does it take for the LPS to reach full intensity?
7-10 minutes
110
What is the coating on the outer envelope of the LPS called?
Indium tin oxide.
111
Which lamps are HID’s?
Mercury Vapor, metal halide, HpS
112
How many watts are mercury Vapor usually?
40-1000w
113
How many watts are metal halide usually?
175-1500w
114
How many watts are HPS usually?
35-1000w
115
What is the visual difference between mercury Vapor and metal halide?
The length of the arc tube. Mercury Vapor is long, and metal halide is shorter and stubby
116
HID’s operate at high _____ and ______
Pressure and temperature
117
How does a mercury Vapor lamp work?
Ballast creates high starting voltage, arc flows through starting electrode and resistor, the arc warms up the argon gas, then the mercury becomes hit enough to vaporize. Then it arcs between the other two electrodes, the light source come right from the strength of the arc.
118
How long does the mercury Vapor lamp take to warm up?
3-7 minutes
119
What is the colour temperature of a mercury Vapor?
A bright white blue light. 6800 K.
Phosphor coating can be added to improve light.
120
Which lamps have a restrike time?
Mercury Vapor: 4-6 minutes.
Metal Halide: 15 minutes.
121
What is the efficacy of the Mercury Vapor?
30-65 l/W
122
What is the life of a mercury Vapor lamp?
24000 hours
123
What gas is added to the Metal Halide lamp?
Halogen.
124
What is the purpose of halogen gas in a metal halide?
Improves efficacy and CRI.
125
What is the colour temperature of metal halides?
4000 K
126
Which lamp has the best CRI of the HID’s?
Metal Halide.
127
What is the life of a metal halide?
15000 - 20000 hours
128
How does a metal halide lamp work?
Ballast creates high striking voltage (higher than mercury vapor), and arc is created through the argon gas, the argon gas discharge fills the whole tube with a dim blue glow. As the lamp heats up the mercury begins to vaporize, as the temperature continues to rise the halide salts begins to vaporize, the lamp becomes an orange glow.
129
What is the start up time of a metal halide?
5-7 minutes
130
What is the difference of pulse start metal halides to standard metal halides?
Better colour uniformity, faster warm up times, improved lumen maintenance, efficacy and lamp life are 50% higher than standard metal halides.
131
What is the main difference between mercury Vapor and metal halides, and HPS?
HPS does not have a starting electrode.
132
What is the startin voltage from the ballast in an HPS?
About 2500V
133
What gases are in a HPS?
Xenon gas, small amount of mercury sodium amalgam
134
What is the purpose of the mercury sodium amalgam?
The blue light from mercury, and yellow light from sodium mix and create a nice light.
135
What is the life of a HPS?
About 24000 hours.
136
Which lamp has the highest efficacy?
LPS
137
Which HID lamp has the longest life?
Mercury Vapor
138
How long does it take an LpS to warm up?
10 minutes
139
Average life of Hps
24000
140
What is the melting point of tungsten
3500 degrees
141
Which lamp has best colour rendition?
Incandescent
