Prelim Flashcards
Defined as the intensity of light per unit area. Referred as lighting or man-made lighting
Illumination
The optimization of energy consumption, with no sacrifice in lighting quality
Energy efficiency
The amount of illumination or luminous flux per unit area.
Quantity of light
The distribution of brightness in the lightning installation or the mixture of all the items related to illumination.
Quality of light
What are the four factors that affect illumination
> Brightness
Contrast
Glare
Diffuseness
What are the six elements that quality of light includes
>Brightness >Glare >Color >Psychological reaction to color and fixtures >Contrast >Diffuseness
It is the light that seems to radiate from the object being viewed
Brightness
The difference in brightness of the brightness ratio between an object and its background
Contrast
It is a strong, steady, dazzling light or reflection. An excessive luminance and or excessive luminance ratio in the field of vision.
Glare
An annoying brightness of light in a person’s normal field of vision
Direct Glare
A more serious and difficult to control brightness reflected by a glossy object
Indirect or Reflected Glare
It is the control of shadows cast by light.
Diffuseness
A radiant energy that is capable of exciting the retina and producing a visual sensation
Light
The visible portion of the electromagnetic spectrum extends from ___ to about ___ nanometers.
380 - 780 nanometers
In the electromagnetic spectrum, Light is located between ______ and ______ radiation
Ultraviolet - Infrared radiation
Longer wavelengths results to
Lower frequency and Lower energy
Shorter wavelengths results to
Higher frequency and Higher energy
1 watt at 555 nanometers is equivalent to how many lumens
683.0 lumens
What are the three types of reflection
> Specular
Spread
Diffuse
It is when an incident light hits an object and bounces off
Reflection
It is the region with slightly shorter wavelength immediately adjacent to the violent end of the visible spectrum
Ultraviolet
Shortest wavelengths (380 - 450 nm)
Violet
Longest wavelengths (630 - 770 nm)
Red
Wavelengths (450 - 490 nm)
Blue
Wavelengths (490 - 560 nm)
Green
Wavelengths (560 - 590 nm)
Yellow
Wavelengths (590 - 630 nm)
Orange
The least harmful and most commonly found type of UV light, often called black light for its relative harmlessness and ability to cause fluorescent materials to emit visible light.
UV-A
The most destructive form of UV for it is enough to damage biological tissue.
UV-B
A type of UV that is almost completely absorbed in air within a few hundred meters.
UV-C
The region with slightly longer wavelengths immediately adjacent to the red end of the visible spectrum
Infrared
The longest wavelengths in the electromagnetic spectrum.
Radio Waves
It has much higher energy and shorted wavelengths than ultraviolet light which lengths between (0.03 - 3) nanometers.
X - rays
The smallest wavelengths and the most energy of any wave in the electromagnetic spectrum.
Gamma Rays
It falls in the range of the electromagnetic spectrum between radio and infrared light.
Microwaves
It is the measure of capability of a material to transmit incident light
Transmittance
It is the measure of total light reflected
Reflectance
It occurs when light is reflected away from the surface at the same angle as the incoming light’s angle
Specular reflection
It occurs when an uneven surface reflects light at more than one angle
Spread reflection
It occurs when a rough or matte surface reflects the light at many different angles
Diffuse reflection
Diffuse Reflection is sometimes called
Lambertian Scattering
It demonstrates the law of reflection, which states that the angle between the incident ray and a line that is normal to the surface is equal to the angle between the reflected ray and normal.
Specular reflection
It occurs when photons from the incident light hit atoms and molecules and cause them to vibrate.
Absorption
This occurs when light waves changes direction as they pass from one medium to another.
Refraction
It is the ratio of the speed of light in a vacuum to the speed of light in the material
Index of refraction
It shows the relationship between the incident angle and the refractive index
Snell’s law
It occurs when light passes through an object that absorption, refraction, reflection and diffusion occur at once.
Transmission
Instead of completely transmitting light, an object can absorb part or all of the incident light, usually by converting it into _____.
Heat
It occurs when light strikes a rough surface and the light is reflected or transmitted in many different direction at once.
Diffusion
It it the bending and spreading of waves around an obstacle
Diffraction
It occurs when light bounces off an object in a variety of directions
Scattering
What are the Three broad methods of illumination
> General Lighting
Local Lighting
Combined General and Local Lighting
It is a part of the eye that the ray of light enters
Cornea
It is the ability of the eye to adjust to higher or lower levels of luminance
Adaptation
The ability of the eye to focus sharply on distant or close objects
Accommodation
The cones operate during the day and nominal daylight conditions and enables us to see in detailed color.
Photopic Vision
It is the receptors of the retina
Rods and Cones
If light conditions are not bright , as the rods can only “ see” a black and white image. what vision is used
Mesopic Vision
The eyes losses all its facility to see in color.
Scotopic Vision
A special branch of radiometry in which visible light is being measured
Photometry
It is the measurement on how much flux (lumens) is emitted within a small conical angle in a particular direction from a light source or luminaire
Luminous Intensity
It is the unit of measurement of Luminous Intensity
Candela
It is the measurement of the visible light outputs of lamps, where light is not directional. It refers to the visible light emitted in all directions at any given moment
Luminous Flux
It is the total radiation being emitted from a light in all directions
Radiant Flux
It is the unit of measurement of Luminous Flux
Lumens
It is the density of Luminous power
Illuminance
It is the unit of measurement of Illuminance
Lux
It is the measure of the amount of light emitted from a surface
Luminance
It is the unit measurement of Luminance
> Candela per square meter
>Footlambert
1 footlambert is equivalent to how many candela per square meter
3.4263 cd/m^2
Designed to give uniform and generally, diffuse lighting throughout the area under consideration.
General Lighting
Provide a restricted area of relatively high intensity
Local Lighting
Used in spaces where the general visual task is low, but supplementary is required in a limited area for particular task.
Combined General and Local Lighting
A material that absorbs some wavelengths and transmits others
Transmissive Filter
A material that absorbs some wavelengths and reflects others
Reflective Filter
