Electromagnetic radiation that can be detected by the human eye

Unit of Light or Luminous Flux from 1m^2 of a 1m^2 surface of 1 candela

Unit of Density of Light

the amount of lumens falling on an area one square foot one foot away

the amount of lumens falling on an area one square meter one meter away

Unit of Light Intensity

Unit of Brightness

quantitative unit for measuring flow of light energy emanating from 1 ft^2 of a 1 ft^2 surface of 1 candlepower/light output

luminous power per unit solid angle emitted by a point light source in a particular direction - CANDELA

measure of light intensity that hits or passes through a surface; LUX - one lumen per square meter

measure of light intensity emitted from a surface per unit area in a given direction; Candela per square meter

1 lumen of luminous flux spread uniformly over an area of 1ft^2

1 lumen spread over 1m^2, the illumination is expressed in lux (lx)

bending of a ray of light as it passes obliquely through a material

when light bounces of an object

“regular reflection” (observed in mirror) angle of reflection = angle of incident light

reflected light is scattered in all directions

Identify:

Identify:

darker objects absorb more than lighter colored objects

ratio of light *transmitted through a material

light passes through clear, transparent materials; angle at which the light leaves is the same as that at which it enters

transmitted light is scattered evenly; Materials that transmit light are known as “translucent”

When the illumination is on a surface, the lumens per square foot are measured

When brightness is from a surface, the lumens per square foot are measured

also called “reflection factor”; it is the ratio of light reflected by a surface to the light falling upon it

also called “transmission factor”; it is the ratio of light transmitted to light striking the surface

effect of brightness in the field of vision which causes annoyance or discomfort, or in worse cases, interferes with seeing

warmness or coolness of white light

for comfortable living

neutral basic lighting in living areas

for pure concentration and vitality

quantitative measure of the ability of a light source to reveal the colours of various objects faithfully in comparison with an ideal or natural light source

amount of light emitted by a lamp

Lamp Life (in hours) of: Incandescent

Lamp Life (in hours) of: Fluorescent

Lamp Life (in hours) of: CFL

Lamp Life (in hours) of: Halogen, Low Voltage

Lamp Life (in hours) of: Halogen, High Voltage

Lamp Life (in hours) of: Mercury Vapor

Lamp Life (in hours) of: Metal Halide

Lamp Life (in hours) of: Sodium Vapor

Lamp Life (in hours) of: LED

Used where color matching is important; equivalent to a north sky; not in general use because of high proportion of blue

combines high efficiency with good color rendering; used in factories, offices, schools; rather cold in appearance

less efficient than daylight by 20%; has better color rendering properties in the long wavelengths; used in stores and some factories where color is important

highest efficiency lamp; often used in factories and offices

high efficiency lamp; only moderate color rendering; poor with reds - emphasis is yellow and yellow-greens; used in offices

most efficient lamp; closest approximation to tungsten filament color rendering; suitable for homes, restaurants, hotels