L1 - Lighting Pop Quiz Flashcards
Name 4 factors that affect visibility
- Size
- Brightness
- Contrast
- Time
What is another name for colour temperature?
Chromacity
An objective specification of the quality of a color regardless of its luminance.
What are the three primary colors
Red, green and blue
What is the CRI and what does it express?
CRI - Color Rendition Index
Expresses the ability of a light source to portray color to a reference
What is Luminous Flux?
Quantity of light output from source.
Define the time rate flow of light.
Unit: Lumen
- 1 Lux = 10.76 Lumen
- 1 Lux = 1 Lum / SQ m
- E (Lux) = I (light intensity in Candella) / D^2 (distance in metres)
What is Luminous Flux Density?
- Luminous flux per unit area at a point of surface.
- The illumination on a surface
- Unit: Lx ( Lux)
- 1 Lux = 10,76 Lumen
- 1 Lux = 1 Lum / S Q m
What does the term efficacy mean?
The ratio of light output ( Lumen) to light input ( in Watts)
What color is the human eye most sensitive to?
Yello and Green ranges
What instrument is the the used of measure lighting levels?
Photometer; Luxmeter
What does the term luminaire mean?
The complete light fixture, ballast, shade, bulb etc
Name the 2 main causes of lighting loss
1 - Dirty fixture; luminaire dirt depreciation
2 - Lamp lumen depreciation
The code consisting of a letter and a number refers to what with regard to bulb?
Shape and size
Filaments are generally made up of what material?
Tungsten; used for electrical contacts and electrodes due its high melting point and low thermal expansion.
What does the gas inside the incandescent bulb do?
- Reduces filament evaporation
What is the inside of a frosted bulb coated with?
Silica powder
What is the purpose of diffuse lighting?
To reduce glare and brightness
Name these bulb shapes by code letter
S - Straight
F - Flame
PAR - Parabolic Aluminized
T - Tubular
G - Global
The general service fixture comes in a number of different types of bases. Name them
- Medium
- Mogul
- Candelbra
- Intermediate
Why do we wire the grounded conductor to the shell of a lamp holder?
- To prevent accidental shock
Which produces more light?
3-50W or 1-150W bulb?
- 1-150w bulb
-Higher efficacy ( Lumen per Watt)
What is another name for a tungsten halogen lamp?
Quartz halogen
A tungsten filament bulb is filled with what gas?
Argon
Explain the regenerative cycle of the tungsten halogen bulb
- Tungsten evaporates and halogen gas combines to return it to the filament.
Why is necessary not to touch the bulb with your fingers?
- Oils from the skin damage the bulb features
What type of switch does the code require for switching lights?
‘ T ’ type [14 - 508 (b) ]
What does the Code say with regards to switching the grounded conductor?
- Only switch the underground conductor
Where is a lighting contactor required?
When you have a large bank of lights
In fluorescent lighting, what material is used in the tube to assist in the initiation of current flow?
Argon gas
What material is used in the tube to transform UV radiation into visible light?
Phosphor coating
Name 3 types of fluorescent tubes
- Circline
- Straight
- U-Shaped
Name 3 types of fluorescent tubes bases
- Single pin
- Double pin
- Recessed socket
Name 3 types of ballasts used in fluorescent lighting
- Preheat
- Instant start
- Rapid start
Why do we not used single tube fluorescent fixtures around moving machinery?
- To reduce the stobe effect of the tube
Low pressure sodium lamp have an efficacy close to what?
200 lumens
The spring loaded socket end of a fluorescent fixture is the X voltage end.
HIGH
What does OCV stand for
Open Circuit Voltage; refers to voltage across the terminals of a battery when the circuit is open ( the battery is not under load).
What is the major cause of ballast failure?
Ambient heat
What does HID stand for?
High Intensity Discharge, which indicates that bulbs are brighter than standard headlights.
Which type of HID lighting has the best color rendition
Metal halide
What is the physical difference between metal halide and mercury vapour bulbs?
Metal halide tube is smaller in size
Name the bulbs by letter code
B - bullet
BT - Bulged tubular
E - Elliptical
PAR - Parabolic Aluminized Reflector
T - Tubular
What does ANSI stand for?
American National Standards Institute
Interpret this code: H36 BT-1000/DX
H - Mercury
36 - Ballast
BT - Bulged Tubular
1000 - 1000Watts
DX - Deluxe
Name three type of ballasts and describe how they work.
- Reactor:
. Used only with mercury vapour
. Sometimes called a ‘lagr’ reactor
. Suitable when line voltage is suitable for striking voltage
. Acts as a choke
. 240240 v or greater - Autotransformer
. Used with mercury vapour
. Voltage doesn’t vary more than 5%
. Larger and more expensive - Auto Regulator
. Metal Halide
. Allows for voltage dips of 40-50% without ‘extincisline’ the bulb
What is the fundamental difference between HPS and the other HID lights?
HPS has no starting electrode
‘Both Metal Halide and High Pressure Sodium bulbs are part of the HID family of bulbs. The primary visual difference between them is that metal halide light is white and the light emitted from a High Pressure Sodium bulb is amber orange. The lamp works by creating an electric arc through vaporized sodium metal.’
What happens when you have a ballast that has 2 bulbs in series and 1 bulb goes out?
They both go out
