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Electrical Year 2 > Lighting > Flashcards

Lighting Flashcards

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
Q

Code letter S

A

Straight side

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26
Q

Code letter F

A

Flame-shaped

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27
Q

Code letter G

A

Globular

28
Q

Code letter A

A

Standard line

29
Q

Code letter T

A

Tubular

30
Q

Code letter PS

A

Pear shaped

31
Q

Code letter PAR

A

Parabolic

32
Q

Code letter R

A

Reflector

33
Q

Lamp bases

A

Normally made of Aluminum or brass, cemented into the bulb.

34
Q

What is the most common used base?

A

Edison base

35
Q

What temp coefficient do incandescent lamps have?

A

positive temperature coefficient. When the lamp is cold, it draws more current than when it is warm.

36
Q

What lamps have a higher efficacy?

A

Higher wattage lamps have a higher efficacy than low wattage lamps of the same voltage.

37
Q

Tungsten-halogen lamp

A

Special type of incandescent lamp. It is a compact, high intensity light source that provides a white light output with high lumen maintenance.

38
Q

What are heat deflectors?

A

They deflect heat away from the base.

39
Q

What is the melting point of tungsten?

A

3500C

40
Q

What normally ends the life of an incandescent lamp?

A

Evaporation of filament

41
Q

For the same wattage, which lamp would last longer, a 120V or 12V?

A

120V

42
Q

Why is continuous dimming not recommended for tungsten-halogen lamps?

A

It prevents the regeneration process.

43
Q

What is a ballast?

A

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
Q

What are the ballast noise ratings?

A

A for quietest and F for noisiest

45
Q

What is the stroboscopic effect?

A

When repetitive flashes of light make moving machinery appear to be stopped.

46
Q

What is the average life of a Low pressure sodium LPS lamp?

A

18000 hours

47
Q

What are the three most common fluorescent lamp bases.

A

Bipin
single pin
recessed

48
Q

What is a major cause of premature ballast failure?

A

High ambient temperature.

49
Q

What are the three classifications of flourescent fixtures?

A

Preheat start
instant start
rapid start

50
Q

What is the rated life of a mercury vapor lamp?

A

24000 hrs plus

51
Q

What is the initial high voltage spike of a high-pressure sodium lamp?

A

2500 volts or more

52
Q

What does BU and BD mean?

A

BU- Base up

BD- Base down

53
Q

Which of the HID lamps has the lowest efficacy?

A

Mercury Vapor

54
Q

Which HID lamp is the best for colour rendition?

A

Metal Halide

55
Q

Which HID lamp has the shortest re-ignition time after a power failure?

A

High-pressure sodium

56
Q

What type of ballast does a pulse start metal halide lamp require?

A

Pulse start ballast

57
Q

Which HID lamp has the longest rated life? which has the shortest?

A

Mercury vapor longest

Metal halide shortest

58
Q

A metal halide bulb is identified as BT-37. What does it mean?

A 
BT= Bulged Tubular
37= 37 eights of an inch diameter
59
Q

Which HID lamp requireas a ballast that produces brief high-voltage spikes to ignite the lamp?

A

High Pressure Sodium Lamp. 2500 to 4000 V for 1-4 microseconds.

60
Q

What is the function of the capacitor when used in conjunction with the ballast wiring?

A

to improve power factor

61
Q

What is the first thing to do if a HID lamp fails to light?

A

Try a new lamp

62
Q

If the voltage at the lamp socket is less than ___% of the required OCV, the ballast should be replaced

A

90

63
Q

What type of light source is LED lighting?

A

Electro chemical light

64
Q

What is the approximate efficacy of LED lighting?

A

75 to 150 lumens per watt

65
Q

What type of light source is induction lighting?

A

gas discharge and electromagnetic induction

66
Q

what is the approximate efficacy of induction lighting?

A

65-70 lumens per watt

Electrical Year 2 (3 decks)

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