chap 4.9

Question 1

Is a graphical representation that illustrates the luminous intensity around the
cross- section of a lamp or luminaire.

Answer 1

Candlepower (Candela) Distribution Curve

Question 2

90 to 100% of the light is directed downward for maximum use

Answer 2

 Direct

Question 3

90 to 100% of the light is directed to the ceilings and upper walls and is reflected
to all parts of a room or 90 to 100% of the light is directed downward for
maximum use.

Answer 3

indirect

Question 4

60 to 90% of the light is directed downward with the remainder directed upward

Answer 4

Semidirect

Question 5

Equal portions of the light are directed upward and downward

Answer 5

General diffuse/ direct-indirect

Question 6

Beam projection distance and focusing ability characterize this luminaire

Answer 6

Highlighting

Question 7

Is excessive brightness in the field of vision that causes discomfort or, in extreme
cases, produces a disability from a temporary loss of vision.

Answer 7

 GLARE

Question 8

It is a visual sensation caused by luminance that is sufficiently greater than the
luminance to which the eyes are adapted.

Answer 8

glare

Question 9

Is a rating of a lighting installation expressed as a percentage of individuals
who, when viewing from a specified location and in a specified direction, will be
expected to find it acceptable in terms of discomfort glare.

Answer 9

Visual Comfort Probability (VCP)

Question 10

Guidelines from the ______________________________
are used to compute the VCP.

Answer 10

Illuminating Engineering Society of North America (IESNA)

Question 11

Causes visual discomfort without necessarily impairing vision.

Answer 11

Discomfort glare

Question 12

Occurs when visibility is impaired from excessive brightness.

Answer 12

Disability glare

Question 13

Occurs when excessive light enters the eye directly from a light Source.

Answer 13

Direct glare

Question 14

The result of light entering the eye after reflecting off a glossy surface.

Answer 14

Reflected glare

Question 15

Preventing glare requires special attention to fixture design, selection, and position to
prevent light from entering the glare zone.

Answer 15

 GLARE CONTROL

Question 16

• a zone above a 45° angle from the fixture’s vertical axis.

Answer 16

Glare Zone

Question 17

Typically made from clear UV-stabilized plastics.

Answer 17

Lenses

Question 18

White translucent diffusers are much less efficient than clear lenses, and they
result in relatively low visual comfort probability. (t or f)

Answer 18

t

Question 19

Louvers

Answer 19

slats in a light fixture that create openings for emitting light

Question 20

_________ provide superior glare control and high visual comfort compared with
lensdiffuser systems.

Answer 20

Louvers

Question 21

______________ louvers (with 5 to 7 in cell apertures and depths of 2 to 4
in) provide a good balance between visual comfort and luminaire efficiency

Answer 21

Deep-cell parabolic

Question 22

Opaque or translucent elements that shield a light source from direct view.
They are typically part of the light fixture.

Answer 22

Baffles

Question 23

_______ prevent the light source from throwing light beyond a 30° angle from the
fixture’s vertical axis.

Answer 23

Baffle