Question 1

When 900 lumen falls onto a 2.0 m² surface from a fluorescent lamp, and a light meter finds that 360 lumen are reflected, the luminance of the surface is: A)3 B)0.71 C)0.4 D)0.2 E)1.25

Accepted Answer

C

Question 2

Light falling onto the surface in a room:&#10;A)Some is absorbed and some reflected&#10;B)Is all absorbed&#10;C)Is all reflected&#10;D)Bounces off at same angle as it arrives&#10;E)Displays the colour of the surface material

Accepted Answer

When light falls onto the surface in a room, some of it is absorbed by the surface material and converted into heat, while the remaining amount is reflected in various directions. This process happens for all types of materials, including opaque, translucent, and transparent ones. Therefore, option A is the best choice as it accurately describes the interaction of light with surfaces in a room.

Question 3

Illumination Intensity is which? A)Lumens B)Light level C)Illuminance D)Lumen/m² E)Lumen per watt

Accepted Answer

Illumination intensity is measured in illuminance, which is the measurement of the amount of light falling on a surface per unit area. Lumens measure the total amount of light emitted by a source, while light level is a subjective term that can refer to the perceived brightness of an environment. Lumen per watt is a measure of the efficiency of a light source. The option D is not a valid unit of measurement.

Question 4

Efficacy of a lamp means?&#10;A)Lumens light output per watt of electrical input power to lamp&#10;B)Efficiency at converting colour temperature into illuminance on the working plane&#10;C)Percentage of lamp globe or tube surface area that emits light&#10;D)Proportion of lamp light output directed toward the working plane&#10;E)Luminous efficacy is total illuminance produced divided by lamp electrical input power including all control equipment consumption

Accepted Answer

Efficacy of a lamp refers to the lumens of light output per watt of electrical input power to the lamp, which is a measure of how efficiently a lamp converts electrical energy into visible light.

Question 5

Light system glare means?&#10;A)Florescent indoor lighting systems do not cause glare&#10;B)Whether discomfort is created in a particular viewing direction&#10;C)Sedentary position includes direct view of sunshine&#10;D)Impairment of vision due to excessive brightness&#10;E)All lighting causes glare when viewed directly

Accepted Answer

Light system glare refers to the impairment of vision due to excessive brightness.

Question 6

What is an air-handling luminaire?&#10;A)Sealed luminaire to keep out moisture&#10;B)A sealed light fitting inside an air handling unit to allow servicing work&#10;C)A light fitting open to the room air allowing cooling&#10;D)Lamp designed for low temperature operation&#10;E)Luminaire passing air returning to the ductwork system from the conditioned room

Accepted Answer

An air-handling luminaire is a light fixture specifically designed to allow the passage of air returning to the HVAC system from the conditioned room. It is an integral part of the HVAC system and is responsible for providing lighting while also maintaining air quality and flow. Option E is the best choice as it accurately describes an air-handling luminaire.

Question 7

What is meant by lamp colour temperature?&#10;A)Colour shift in surface caused by the type of lamp&#10;B)Description of colour-rendering property&#10;C)Colour of the lamp when viewed directly&#10;D)Infra-red fraction of the sun produced by the lamp&#10;E)Calculated average temperature from each of eight wavelength bands in the light produced by a lamp

Accepted Answer

Lamp colour temperature refers to the description of the colour-rendering property of a lamp, usually measured in Kelvin (K). It describes the warmth or coolness of the light produced by the lamp, with lower Kelvin values indicating warmer light (yellow to orange) and higher Kelvin values indicating cooler light (blue to white).

Question 8

Which are correct descriptions of lighting system sensor operation?&#10;A)People in office workstations cannot be seen by infra-red, microwave and acoustic sensors&#10;B)Frequent switching of fluorescent lighting does not work&#10;C)Correctly placed occupancy sensors ensures safe access at all times and fluorescent lamps switch on very quickly&#10;D)Fluorescent lamps take too long to switch on for automatic sensing systems to work efficiently and people have to walk into a dark room&#10;E)Unoccupied rooms should not remain without lighting as they are an invitation to burglars

Accepted Answer

Correctly placed occupancy sensors can detect movement and ensure that the fluorescent lamps switch on quickly, which can create a safer environment. Option A is incorrect because some sensors can detect people through infrared and microwave technology. Option B is incorrect because frequent switching of fluorescent lighting can work with the proper equipment. Option D is incorrect because some automatic sensing systems can work efficiently with fluorescent lights, and people do not have to walk into a dark room. Option E is also incorrect because unoccupied rooms should not have lighting on all the time as it is wasteful and unnecessary.

Question 9

Which is correct about lighting? A)1000 lumen/m² is a very bright indoor illumination level B)1000 lux is a very dull indoor illumination C)A typical fluorescent tube emits about one million lumens D)Fluorescent lighting does not cast shadows E)LED lighting is very energy-inefficient

Accepted Answer

1000 lumen/m² is a very bright indoor illumination level. Answer: D Fluorescent lighting does cast shadows. In fact, the direction of the light source can greatly affect the intensity and direction of shadows.

Question 10

Which of these correctly describe BZ classification?&#10;A)BZ 5 projects only sideways and is used for wall mounted luminaires&#10;B)BZ 0 means equal spherical illuminance&#10;C)BZ 10 means light projection all downwards&#10;D)BZ 10 has a luminaire directing all light output upwards providing only reflection off the ceiling&#10;E)BZ defines the solid angle projection from a lamp in streradians

Accepted Answer

The answer of Which of these correctly describe BZ classification?&#10;A)BZ...

Deck 10: Lighting