Lighting Science_old

Question 1

Which of the following is the BEST definition of
illuminance?
A. luminous flux density incident on an object per unit area
B. flux density emitted from an object without regard for direction
C. flux density emitted from an object in a given direction
D. time rate of flow of light energy

Answer 1

A. luminous flux density incident on an object per unit area

Question 2

A ray of incident light being reflected in one distinct
direction is representative of which of the following types of reflection?
A. spread
B. diffuse
C. specular
D. semi-specular

Answer 2

C. specular

Question 3

IES Standard IES-LM-80 provides LED fixture
manufacturers a method to
A. measure lumen maintenance.
B. identify gamut area.
C. quantify fidelity.
D. define efficacy.

Answer 3

A. measure lumen maintenance.

Question 4

15. Which of the following color sample sets is used to
calculate the CRI/Ra of a light source?
A. R1-R8
B. R1-R9
C. R1-R14
D. R1-R99

Answer 4

A. R1-R8

Question 5

Which type of vision would predominantly be used at very low light levels?
A. Scotopic
B. Photopic
C. Mesopic
D. Meso-optic

Answer 5

A. Scotopic

Question 6

What does CCT stand for?
A. Color Correction Table
B. Color Co-efficient
C. Creedance Clearwater Techno-pop
D. Correlated Color Temperature

Answer 6

D. Correlated Color Temperature

Question 7

Which of these metrics measures the total light emitting from a light source?
A. Luminance
B. Luminous Intensity
C. Illuminance
D. Luminous Flux

Answer 7

D. Luminous Flux

Question 8

5) How many lux are in one foot-candle?
A. 1/10th
B. 10.76
C. A dozen
D. 1

Answer 8

A. 10.76

Question 9

A lamp’s ability to generate light is measured in?
A. Efficacy
B. Efficiency
C. Co-Efficient of Utilization
D. Einsteiniums

Answer 9

B. Efficacy

Question 10

Diffusers utilize this process to control light.
A. Attraction
B. Reflection
C. Absorption
D. Refraction

Answer 10

D. Refraction

Question 11

Which is not a manner to obtain white light with LEDs?
A. Red, Green, Blue LEDs
B. Blue LEDs with yellow phosphors
C. Green LEDs with blue and red phosphors
D. UV LED with multi-component phosphors

Answer 11

C. Green LEDs with blue and red phosphors (Need to confirm)

Question 12

Two objects match in color appearance under a
fluorescent light source with a specific CRI and correlated
color temperature. Under which of the following light
sources would these objects MOST likely be expected to
match?
A. LED
B. halogen IR
C. reference lamp
D. ceramic metal halide

Answer 12

C. Reference Lamp

Question 13

Photo sensor quantities of 120 million per eye and 8 million per eye relate to
A. Scotopic vision, Photopic Vision
B. Photopic vision, Scotopic Vision

Answer 13

A. Scotopic Vision, Photopic Vision

Question 14

The type of vision for low light levels and limited ability to discern detail and color, High light level and ability to see fine detail and color, both are?
A. Photopic, Mesoptic, Scotopic
B. Scotopic, Photopic, Mesoptic
C. Scotopic, Mesoptic, Photopic
D. Photopic, Scotopic, Mesoptic

Answer 14

B. Scotopic, Photopic, Mesoptic

Question 15

Rods and Cones are located:
A) Rods distributed widely across retina except for foveva. Cones distributed across retina but strongly concentrated in fovea.
B) Cones distributed widely across retina except for foveva. Rods distributed across retina but strongly concentrated in fovea.
C) Rods and cones both distributed widely across retina
D) Rods and cones both distributed across retina but strongly concentrated in fovea

Answer 15

A) Rods distributed widely across retina except for foveva. Cones distributed across retina but strongly concentrated in fovea.

Question 16

Luminous intensity

Answer 16

The luminous flux per unit solid angle in the direction in question. Hence, it is the luminous flux on a small surface centered on and normal to that direction, divided by the solid angle (in steradians) that the surface subtends at the source. Luminous intensity may be expressed in candelas (cd) or in lumens per steradian (lm/sr).

Question 17

Illuminance

Answer 17

The areal density of the luminous flux incident at a point on a surface. (lux, ft-cd)

Question 18

Luminance

Answer 18

The quotient of the luminous flux at an element of the surface surrounding the point, and propagated in directions defined by an elementary cone containing the given direction, by the product of the solid angle of the cone and the area of the orthogonal projection of the element of the surface on a plane perpendicular to the given direction. The luminous flux may be leaving, passing through, and/or arriving at the surface. (cd/m2)