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Electrical Year 2 > Lighting > Flashcards

Lighting Flashcards

(66 cards)

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1
Q

Which part of the eye is the light sensitive surface where the image is projected onto at the back of the eye

A

Retina

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2
Q

Coloured portion that functions as a diaphragm to control the amount of light

A

Iris

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3
Q

Opening in the centre of the iris where light enters the eye

A

Pupil

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4
Q

transparent capsule behind the iris that is used to focus the image

A

Lens

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5
Q

What are the four main factors that affect visibility?

A

Size
Brightness
Contrast
Time

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6
Q

What two important features does a good lighting system provide?

A

Quantity and Quality of light

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7
Q

What is colour rendidtion?

A

The ability of a light source to portray the colour appearance of objects accurately

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8
Q

What colour temperature is a metal halide (400 W, clear)

A

4300 cool

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9
Q

What is colour temperature?

A

Below 3000 K is warm colour. Above 4000 K is cool colour.

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10
Q

What light has the best CRI?

A

Incandescent lamps

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11
Q

Metal halide (400 W, clear)

A

CRI 65, good

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12
Q

High pressure sodium

A

CRI 32, poor

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13
Q

Mercury vapour

A

CRI 22, poor

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14
Q

Inverse square law

A

illumination is inversely proportional to the square of the distance between the light source and the work surface
E=I/d2

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15
Q

What has the higher frequency, infrared of ultraviolet?

A

ultraviolet

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16
Q

What is light output of a lamp measured with?

A

Lumens

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17
Q

The unit for illumination is the

A

lux, lx

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18
Q

What is the lighting level on a work plane measured with?

A

photometre

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19
Q

What is a complete lighting unit called?

A

Luminaire

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20
Q

What are the two main reasons for light loss?

A

Lamp lumen depreciation

Luminaire dirt depreciation

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21
Q

What is the coefficient of utilization?

A

Percentage of initial lamp lumens that reach task area to produce illumination

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22
Q

What is indirect and direct classification of luminaires?

A

Indirect is up. Direct is down

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23
Q

How much energy input is wasted as heat?

A

90%

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24
Q

What are filaments made of?

A

Tungsten

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25
Code letter S
Straight side
26
Code letter F
Flame-shaped
27
Code letter G
Globular
28
Code letter A
Standard line
29
Code letter T
Tubular
30
Code letter PS
Pear shaped
31
Code letter PAR
Parabolic
32
Code letter R
Reflector
33
Lamp bases
Normally made of Aluminum or brass, cemented into the bulb.
34
What is the most common used base?
Edison base
35
What temp coefficient do incandescent lamps have?
positive temperature coefficient. When the lamp is cold, it draws more current than when it is warm.
36
What lamps have a higher efficacy?
Higher wattage lamps have a higher efficacy than low wattage lamps of the same voltage.
37
Tungsten-halogen lamp
Special type of incandescent lamp. It is a compact, high intensity light source that provides a white light output with high lumen maintenance.
38
What are heat deflectors?
They deflect heat away from the base.
39
What is the melting point of tungsten?
3500C
40
What normally ends the life of an incandescent lamp?
Evaporation of filament
41
For the same wattage, which lamp would last longer, a 120V or 12V?
120V
42
Why is continuous dimming not recommended for tungsten-halogen lamps?
It prevents the regeneration process.
43
What is a ballast?
It is needed in all fluorescent lamps. It provides the high starting voltage; and it limits the current in the tube once the tube lights.
44
What are the ballast noise ratings?
A for quietest and F for noisiest
45
What is the stroboscopic effect?
When repetitive flashes of light make moving machinery appear to be stopped.
46
What is the average life of a Low pressure sodium LPS lamp?
18000 hours
47
What are the three most common fluorescent lamp bases.
Bipin single pin recessed
48
What is a major cause of premature ballast failure?
High ambient temperature.
49
What are the three classifications of flourescent fixtures?
Preheat start instant start rapid start
50
What is the rated life of a mercury vapor lamp?
24000 hrs plus
51
What is the initial high voltage spike of a high-pressure sodium lamp?
2500 volts or more
52
What does BU and BD mean?
BU- Base up | BD- Base down
53
Which of the HID lamps has the lowest efficacy?
Mercury Vapor
54
Which HID lamp is the best for colour rendition?
Metal Halide
55
Which HID lamp has the shortest re-ignition time after a power failure?
High-pressure sodium
56
What type of ballast does a pulse start metal halide lamp require?
Pulse start ballast
57
Which HID lamp has the longest rated life? which has the shortest?
Mercury vapor longest | Metal halide shortest
58
A metal halide bulb is identified as BT-37. What does it mean?
``` BT= Bulged Tubular 37= 37 eights of an inch diameter ```
59
Which HID lamp requireas a ballast that produces brief high-voltage spikes to ignite the lamp?
High Pressure Sodium Lamp. 2500 to 4000 V for 1-4 microseconds.
60
What is the function of the capacitor when used in conjunction with the ballast wiring?
to improve power factor
61
What is the first thing to do if a HID lamp fails to light?
Try a new lamp
62
If the voltage at the lamp socket is less than ___% of the required OCV, the ballast should be replaced
90
63
What type of light source is LED lighting?
Electro chemical light
64
What is the approximate efficacy of LED lighting?
75 to 150 lumens per watt
65
What type of light source is induction lighting?
gas discharge and electromagnetic induction
66
what is the approximate efficacy of induction lighting?
65-70 lumens per watt

Electrical Year 2 (3 decks)

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