Lighting Science_old Flashcards
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
A. luminous flux density incident on an object per unit area
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
C. specular
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.
A. measure lumen maintenance.
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
A. R1-R8
Which type of vision would predominantly be used at very low light levels? A. Scotopic B. Photopic C. Mesopic D. Meso-optic
A. Scotopic
What does CCT stand for? A. Color Correction Table B. Color Co-efficient C. Creedance Clearwater Techno-pop D. Correlated Color Temperature
D. Correlated Color Temperature
Which of these metrics measures the total light emitting from a light source? A. Luminance B. Luminous Intensity C. Illuminance D. Luminous Flux
D. Luminous Flux
5) How many lux are in one foot-candle? A. 1/10th B. 10.76 C. A dozen D. 1
A. 10.76
A lamp’s ability to generate light is measured in? A. Efficacy B. Efficiency C. Co-Efficient of Utilization D. Einsteiniums
B. Efficacy
Diffusers utilize this process to control light. A. Attraction B. Reflection C. Absorption D. Refraction
D. Refraction
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
C. Green LEDs with blue and red phosphors (Need to confirm)
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
C. Reference Lamp
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
A. Scotopic Vision, Photopic Vision
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
B. Scotopic, Photopic, Mesoptic
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
A) Rods distributed widely across retina except for foveva. Cones distributed across retina but strongly concentrated in fovea.
Luminous intensity
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).
Illuminance
The areal density of the luminous flux incident at a point on a surface. (lux, ft-cd)
Luminance
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)
