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lighting > Lighting > Flashcards

Lighting Flashcards

1
Q

Which part of the eye is the:

a. light-sensitive surface where the image is projected onto at the back of the eye

b. coloured portion that functions as a diaphragm to control the amount of light entering the eye

c. opening in the centre of the is where light enters the eye

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

A

A) Retina

B) Iris

C) Pupil

D) Lens

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2
Q

State the four main factors considered to affect visibility.

A

Size , brightness, contrast, Time

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3
Q

Which one of the preceding factors is most important when viewing moving objects?

A

Time

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4
Q

What two important features does a good lighting system provide?

A

Brightness, Contrast

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5
Q

Using the electromagnetic spectrum, which is the higher frequency light: infrared or ultraviolet

A

Ultraviolet

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6
Q

The actual colour composition of white light can be seen using a

A

Prism

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7
Q

The human eye is considered to be most responsive to colour range of:
a. purple
b. red
c. orange-red
D. yellow-green

A

Yellow-Green

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8
Q
  1. The “colour” of light is determined by its
A

Wavelength

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9
Q

The total light output of a lamp is measured in

A

Lumens

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10
Q

The unit for illumination is the

A

Lux (Lx) EV

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11
Q

What two values does efficacy compare?

A

light output (lumens)
and pover input

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12
Q

Which of the following types of lamps is considered to provide the best colour rendition?
a. incandescent
b. mercury vapour
c. high-pressure sodium
d. fluorescent -cool white

A

Incandescent

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13
Q

Which of the following light sources is generally considered as having the highest efficacy?
a. incandescent
b. fluorescent
c. mercury vapour
d. high-pressure sodium

A

High Pressure Sodium

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14
Q

The lighting level on a work plane is commonly measured using a

A

Photometre

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15
Q

In simple terms, state what is meant by the:
A) Inverse square law

B) Cosine law

A

A) Illumination is inversly proportional to the square of distance between them

B) The ilumination of any surface varies as the cosie of the angle of incidence, Angle of incidence is between the normal to the surface and the direction of incident light

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16
Q
  1. When referring to wavelengths of light, what is a nanometre?
A

A nanometre is one billionth
of a metre

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17
Q

The two main factors in the design of a lighting system involve both the

A

Quantity of light and quality of light

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18
Q
  1. List three variables (factors) involved in the design of a lighting installation.
A

Area and type of enviourment (indoors or outdoors)

Type of Task (critical seeing or decoration)

Architectural requirements

Costs of installation

Availability

Environmental impact

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19
Q

What are three factors that contribute to the quality of light?

A

Glare

Diffusion

Colour

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20
Q

What two colours are considered to be “cooling”?

A

Blue and green

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21
Q

A complete lighting unit (lamps, reflectors, etc.) is called a

A

Luminaire

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22
Q

What does a distribution curve illustrate?

A

The variation in light density, usually througha vertical axis

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23
Q

What are two important considerations for roadway lighting design?

A

CRI, and light level

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24
Q

What lamp type does not start (light up) immediately?

A

HID High Intesity Discharge

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25
Q

What are the two main causes of light loss over time?

A

Lamp lumen depreciation
Luminaire dirt depreciation

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26
Q

Why is group relamping usually recommended?

A

Minimize disruptions and labour costs

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27
Q

Luminaire efficiency

A

The percentage of total lumens emmited by the luminaire compered do the total lumens geneated by the lamp alone

28
Q

Coefficient of utilization

A

The percentage of lamp lumens that actually reach the area for lighting

29
Q

What is the essential difference between direct and indirect classifications of luminaires?

A

Direct = 0-10%: upward componet and indirect 90-100% upward

30
Q

How is light produced in an incandescent lamp?

A

Passing electric curent through, filament and heating until it glows

31
Q

What percentage of the output of an incandescent lamp is in the form of light? What percentage is in the form of heat?

A

10% is light
90% heat

32
Q

As a light-producing device, the incandescent lamp is:
a. highly efficient

b. moderately efficient

c. very inefficient

A

Very Inefficient

33
Q
  1. What types of gas are used in incandescent lamps, and for what purpose?
A

Argorn and nitrate

34
Q

A 100 W incandescent lamp is designated as G25 on the box. What is the shape and diameter of this lamp

A

Globular 3-1/8

35
Q

Where would you likely locate information about the overall length of a lamp?

A

In the manufacturer’s catalogue

36
Q

What material is the filament normally made of?

A

Tungsten

37
Q

Why are heat deflectors used in some lamps?

A

To deflect heat from base area, where it may losen the cement

38
Q

The glass in lamps used for general purposes is

a. clear

b. diffuse

c. coloured

A

Diffuse

39
Q
  1. Why is the glass identified in the previous question used for general purpose
A

Diffuce glass reduces the brightness of the light source by effectively incresing the surface area of the bulb (reduce glare)

40
Q

The melting point of tungsten is closest to:

A

3500

41
Q

How does a green incandescent lamp produce that colour light?

A

other colours are absorted by glass, only green is let out

42
Q

The most common lamp base is the

A

screw type or edison base

43
Q

Name a typical application for each of the following lamp bases:

a. mogul

b. prefocus

c. three-contact screw base

A

high wattage lamps = mogul

Projector lamps = prefocus

Trilight lamps = three-contact screw base

44
Q

The higher the temperature of the lamp filament, the output and the. lamp life.

A

Higher the light and lower the lamp life

45
Q

What normally ends the life of an incandescent lamp?

A

evaporation of the Filament reduces the filament diameter to the breaking point, end of life occurs when the filement finally breaks

46
Q

Lumen maintenance or maintained lumens are highest when a general service lamp is operated

A

With the base up

47
Q

State a reason why the light output of an incandescent diminishes over the life of the lamp.

A

Tungsten evaporating From the filament sticks to the inside of the glass bulb and blocks percentage of light emmissions

48
Q

Which of the following combinations of incandescent lamps produces the most light

A

One 150 W

49
Q

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

A

12 Volt

50
Q

Another name for the tungsten-halogen lamp is the

A

Quartz halogen
lamp.

51
Q

What is the regenerative cycle action in the tungsten-halogen lamp

A

Evaporated Tungsten from the filament combining with the halogen and being redeposited in the filament

52
Q

Explain why a tungsten halogen lamp has high lumen maintenance compared to a standard incandescent

A

wall blackening reduces light output , so that’s why lumen maintenance is higher in tungsten halogen incandescent

53
Q

Typical lamp life of a typical 1500 W tungsten-halogen lamp would be closest to

A

2500 hours

54
Q

What feature of quartz glass makes it suitable for the tungsten-halogen lamp?

A

High melting temperature

55
Q

Why must the tungsten-halogen lamp be enclosed in a reflector or similar enclosure?

A

The possibility of the lamp shattering at normal end of life

56
Q

The dominant colour of the light from a tungsten-halogen source is

A

White

57
Q

Why is continuous dimming not recommended for tungsten-halogen lamp

A

Reduced temperature may prevent the regenerative cycle action

58
Q

What condition is finger contact with cold quartz glass likely to cause?

A

Premature glass breakage and/or glass discolouration

59
Q

Why must tungsten-halogen lamps be de-energized before installation or replacement?

A

Severe burns if skin contact is made

60
Q

Explain the lamp designation MR16.

A

multi Faceted reflector 16/ 8th” inches

61
Q

What type of light source is LED lighting?

A

Electrochemical

62
Q

What is the approximate efficacy of LED lighting?

A

75-150 lumens/Watt

63
Q

List four advantages of LED lighting.

A

Low power consumption

Available in all colours

Fully dimmable

Resistant to damage from shock and vibration

64
Q

List three disadvantages of LED lighting.

A

More expensive

Very heat sensitive

Typically cast light in one direction

65
Q

List four applications for LED lighting.

A

Traffic Signal lamps

Exit Signs

Road lights

Security lighting

lighting (1 decks)

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