LT1-5

Question 1

Light enters through the ___?

Answer 1

Cornea

Question 2

What does the retina do?

Answer 2

Forms the optical image

Question 3

WHat are 4 factors that affect visiblilty

Answer 3

Size, brightness, contrast, time

Question 4

poor lighting causes the eye muscles to become ___

Answer 4

Tired and fatigued

Question 5

A good lighting system provides

Answer 5

the quantity, and the quality of light ​

Question 6

Different colours are actually different ____

Answer 6

Wave lengths

Question 7

What is coulour temperature measured in

Answer 7

Kelvin

Question 8

Below 3000K is ______ lIght

Answer 8

soft, warm light

Question 9

Above 4000K is ______ light

Answer 9

Hard, cold light

Question 10

CRI stands for

Answer 10

Colour Rendering Index

Question 11

What is a definiton of CRI

Answer 11

“The ability of a light source to portray the colour appearance of objects accurately when compared to a standard (reference) light source of the same colour temperature.”​

Question 12

Does Low -preassure sodium lighting have a really good or bad CRI

Answer 12

Really bad, its undefined

Question 13

What is total quantity from a light source called and measured in?

Answer 13

Luminous flux, measured in Lumens

Question 14

What is Illumination or lighting level on a surface called and measured in?

Answer 14

Called luminous flux density, measured in Lux

Question 15

What is the device that measures lighting levels called

Answer 15

A photometer

Question 16

What is luminous efficacy the ratio of ?

Answer 16

he ratio of the light output (lumens), to the power input (watts)​

Question 17

How many lumens in 1 watt for 100% effeciency

Answer 17

683 lumens per watt

Question 18

What are some factors in lighting choices (6)

Answer 18

Area and type of environment ​

Type of task ​

Architectural and decorative requirements ​

Costs of operation​

Availability ​

Environmental impact

Question 19

Factors of quality of light (3)

Answer 19

Glare, diffusion, colour

Question 20

What is a complete lighting unit called

Answer 20

Luminaire

Question 21

Four different light sources for luminaires

Answer 21

Incandescent​

Fluorescent ​

High-intensity discharge (HID)​

LED

Question 22

Lamps should be replaced at what % of their rated life

Answer 22

70%

Question 23

WHy is it important to clean light fixtures

Answer 23

can add 30% more light…making sure ventilation is good

Question 24

Why are incadecents bulbs bad

Answer 24

90% of energy is wasted in heat

Question 25

What is the filament in a incandescent usually made out of and why

Answer 25

tungsten, very high melting point of 3419 degrees Celsius​ Low rate of evaporation

Question 26

WHat do the number on light bulb sizes mean?

Answer 26

The max width measured in 1/8ths of and inch ex: 10 = Size = 10x1/8” or 1 ¼”

Question 27

3 different bulb glass

Answer 27

Clear, diffuse, couloured

Question 28

what is the normal lightbulb base called

Answer 28

Medium Edison bass

Question 29

How many watt can a medium bass handle

Answer 29

7.5-300w

Question 30

What is the next size up from medium bass

Answer 30

Mogul

Question 32

Do incandescent lights draw more or less current when they are cold

Answer 32

More. It draws more current than when it is warm due to a low initial filament resistance

Question 33

What does LED stand for

Answer 33

Light emitting diode

Question 34

Efficacy of led ( lumens per watt)

Answer 34

75-150 lumens per watt

Question 35

Efficacy of incandescent ( lumens per watt)

Answer 35

22 lumens per watt

Question 36

Advantages of LEDs

Answer 36

Low power consumption • Negligible early installation failures • Resistant to shock and vibration…no glass or filament to break • LEDs are fully dimmable • Available in all colours • LEDs are cool when operating • They are extra low-voltage • Unwanted light does not bleed off • Deliver directed light for increased system efficiency No moving parts, no toxic gases, no filament to burn, break or fail…nothing that will contaminate the environment • Small size • Extremely long service life (50 000 hours or more) • Instant on/off in their operation • Work well in cold weather….works well from -40 degrees to 185 degrees • LEDs have an acceptable colour redering index…around 70

Question 37

Disadvantages of leds

Answer 37

More expensive • Very heat sensitive • Reflectors or lenses are needed to disperse the light