Light and Illumination Concepts Quiz
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Questions and Answers

Which phenomenon refers to the reflection of light when it bounces off a shiny surface?

  • Diffusion
  • Refraction
  • Reflection (correct)
  • Transmission

Light is always refracted when it passes through any material.

False (B)

What is the term for light that is absorbed by opaque materials?

Absorption

The phenomenon where light is made to travel in a single plane is known as _______.

<p>polarization</p> Signup and view all the answers

What is the initial lumen output of a lamp?

<p>The rated light output when the lamp is new (B)</p> Signup and view all the answers

Match the following light control characteristics with their definitions:

<p>Reflection = Light bouncing off a surface Diffusion = Scattering light in multiple directions Transmission = Light passing through a material Refraction = Change in light direction at a material interface</p> Signup and view all the answers

In polarization, light can pass through all polarizing materials without any effect.

<p>False (B)</p> Signup and view all the answers

What property of light allows it to change direction when it passes from air into glass?

<p>Refraction</p> Signup and view all the answers

What is defined as the time elapsed when 50% of a group of lamps remain burning?

<p>Rated lamp life (C)</p> Signup and view all the answers

Mean lumens refers to the lumens output at 100% of the rated life of the lamp.

<p>False (B)</p> Signup and view all the answers

What is the term for the ratio of total light output of the lamps versus the output of all lamps in the luminaire?

<p>Luminaire efficiency</p> Signup and view all the answers

The loss of light output with time is known as __________.

<p>lumen depreciation</p> Signup and view all the answers

Which measurement indicates how well a lamp renders colors compared to a reference light source?

<p>Color rendering index (CRI) (D)</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Luminous efficacy = Light output per unit of electrical power Color temperature = Color of lamp expressed in kelvins Flicker = Light fluctuations due to cyclical current Beam lumens = Initial lumens output within the central beam</p> Signup and view all the answers

Flicker is normally perceptible in coated HID lamps due to their characteristics.

<p>False (B)</p> Signup and view all the answers

What is the term used to describe the light output within the central beam of a floodlight?

<p>Beam lumens</p> Signup and view all the answers

What is one way to minimize light intensity in lamps?

<p>Using lead lag ballast (C)</p> Signup and view all the answers

Inert gas is used in a bulb to increase the evaporation rate of the filament.

<p>False (B)</p> Signup and view all the answers

What type of base is fitted with a screw pitch for insertion into a socket?

<p>Screw base</p> Signup and view all the answers

The _____ is a decorative bulb that can be used with dimmers or as accent lighting.

<p>Candle</p> Signup and view all the answers

Which of the following is NOT a type of incandescent lamp mentioned?

<p>LED (B)</p> Signup and view all the answers

Match the following components to their descriptions:

<p>Filament = Emits light rays when current passes through Base = Metal end of a light bulb for socket connection Heat deflecting disc = Protects the base from heat Lead-in wire = Electric conductor to the filament</p> Signup and view all the answers

Extended life service bulbs are designed to operate at temperatures significantly lower than 3800°F.

<p>True (A)</p> Signup and view all the answers

What is the expected life span of heavy filament incandescent lamps in extended life service?

<p>2500 to 10,000 hours</p> Signup and view all the answers

What is the primary advantage of using dichroic reflector lamps?

<p>They allow selective color transmission. (A)</p> Signup and view all the answers

Krypton lamps are known for their longevity and high color rendition.

<p>True (A)</p> Signup and view all the answers

What component of a light bulb connects it to the electric circuit?

<p>Base</p> Signup and view all the answers

The gas inserted in the bulb to slow down the evaporation of the filament is called __________.

<p>inert gas</p> Signup and view all the answers

Which type of lamp achieves better energy efficiency than standard incandescent bulbs?

<p>Tungsten halogen lamps (C)</p> Signup and view all the answers

Match the type of lamp with its characteristic.

<p>Dichroic reflector lamp = Transmits color selectively Krypton lamp = Long life and good color rendition Miniature reflector lamp = High efficacy and great color quality Mercury lamp = Uses liquid mercury for vapor</p> Signup and view all the answers

Mercury vapor lamps require high voltage for operation.

<p>True (A)</p> Signup and view all the answers

What is the primary role of the filament support in a light bulb?

<p>Hold the filament in place</p> Signup and view all the answers

What is the primary purpose of the emitter material in a cathode coil?

<p>To emit electrons (A)</p> Signup and view all the answers

Argon is the only inert gas used in fluorescent lamps.

<p>False (B)</p> Signup and view all the answers

What material is the basic phosphor in white fluorescent lamps?

<p>Calcium halophosphate</p> Signup and view all the answers

The ______ is used to connect the lamp to the electric circuit.

<p>base</p> Signup and view all the answers

Which phosphor material is typically used to produce orange light?

<p>Calcium silicate (A)</p> Signup and view all the answers

Match the following components with their functions:

<p>Cathode Shield = Minimizes tube end blackening Ballast = Controls electrical resistance Bulb = Holds the gas Base = Connects lamp to electric circuit</p> Signup and view all the answers

Rare earth phosphors improve lumen maintenance characteristics.

<p>True (A)</p> Signup and view all the answers

How much can rare earth phosphors potentially raise lumen output over conventional halophosphors?

<p>Up to 8%</p> Signup and view all the answers

What is the main function of a ballast in fluorescent lamps?

<p>To start the lamp and regulate the current (C)</p> Signup and view all the answers

Instant start lamps require the electrodes to be heated before operation.

<p>False (B)</p> Signup and view all the answers

What is the ballast factor used for?

<p>To determine the light output for a specific lamp-ballast system relative to rated lumen output.</p> Signup and view all the answers

The __________ of a fluorescent lamp ballast indicates how efficiently it converts electrical power into usable light.

<p>efficacy</p> Signup and view all the answers

What causes the hum emitted by electromagnetic ballasts?

<p>Vibration of the laminated core (A)</p> Signup and view all the answers

Match the following types of lamps with their characteristics:

<p>Rapid start lamps = Have low resistance cathodes and heat continuously Instant start lamps = Do not heat electrodes prior to starting Preheat lamps = Require initial heating before starting Triphosphor lamps = Lower depreciation of luminous flux</p> Signup and view all the answers

Fluorescent lamps are highly efficient and convert a large percentage of input power to light without producing waste heat.

<p>False (B)</p> Signup and view all the answers

What are harmonics in relation to current or voltage wave shapes?

<p>Harmonics are sinusoidal voltages or currents that are higher multiples of the fundamental frequency.</p> Signup and view all the answers

Flashcards

Reflection

Light bouncing off a surface. Shiny surfaces reflect light at equal angles (specular). Matte surfaces scatter light (diffuse).

Diffusion

Light scattering from a non-shiny surface; the light is more scattered or spread out.

Transmission

Light passing through a material. Transparent materials let light through; translucent materials scatter light as it passes through; opaque materials block light.

Absorption

Light being soaked up by a material. The material converts the light into heat.

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Refraction

Light bending when it passes between materials of different densities (like from air to glass).

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Polarization

Light waves vibrating in a single plane instead of all directions. Polarizing filters reduce glare.

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Initial Lumen

The light output of a lamp when it's brand new, usually after 100 hours of use.

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Light Output Units

Measured in Lumens (lm).

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Average lumen

The average light output of a lamp, calculated from the initial and end-of-life lumens.

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Mean lumens

The light output at 40% of the lamp's rated life.

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Beam lumens

Initial light output within a floodlight's central beam.

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Luminous efficacy

Light output per unit of electrical power (lpw).

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Rated lamp life

The time when 50% of lamps in a group are still working.

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Luminaire efficiency

The ratio of a lamp's total light output to the total output from all lamps.

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Lumen depreciation

The decrease in a lamp's light output over time.

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Color temperature

The color of the lamp, measured in kelvins (K).

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Incandescent Lamp Brightness

Brightness of incandescent lamps can be controlled by using lead-lag ballast for multiple lamps, or by wiring fixtures on alternate three-phase circuits.

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Light Intensity Control

Light intensity can be adjusted via multilevel switching or dimming.

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Lead-in wire

Electric conductor carrying current to the lamp filament.

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Inert gas

Gas in a bulb that slows down filament evaporation.

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Filament

Thin metal wire (usually tungsten), that glows when electricity passes through it.

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Bayonet Base

Lamp base with two metal pins for insertion into the socket.

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Screw Base

Lamp base with a screw thread to fit into the socket.

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Rough and Vibration Service Incandescent

Incandescent lamps designed for use in environments with rough handling or vibration.

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Dichroic reflector lamp

A lamp that transmits color selectively through a molecular layer, reducing heat in the light beam.

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Krypton lamp

A long-lasting lamp filled with krypton gas, providing good color rendition.

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MR lamp

A highly efficient, controllable lamp with excellent color quality, used for interior lighting.

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Tungsten Halogen Lamp

An incandescent lamp with improved energy efficiency due to a halogen gas, which increases lamp life.

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Contact

The metal part that establishes electrical connection between the light bulb base and socket.

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Electric circuit

The lamp component that allows electrical current to flow through the filament.

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Inert gas

A gas, like iodine or bromine, inserted into the bulb to slow down filament evaporation.

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Lamp color (CW,D,WW)

Different color temperatures of light used for different applications (cool white, daylight, warm white)

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Cathode/Electrode coil

Coiled tungsten filaments coated with an electron-emitting material, positioned at each end of the lamp.

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Inert gas

Argon or a mix of argon, neon, xenon, and krypton, used to carry the discharge arc in lamps.

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Phosphor Coating

Material that converts ultraviolet light into visible light, determining lamp color.

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Rare Earth Phosphor

Phosphor producing better color and higher light output, useful in smaller lamps.

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Base

Lamp component for electrical connections and lamp holder support, typically aluminum cap or contact pins.

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Bulb

Part of the lamp that holds and contains the gas.

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Cathode Shield

Part that minimizes darkening of lamp ends and reduces flickering.

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Ballast (control gear)

A component that controls the amount of current to the lamp, preventing overheating.

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Rapid Start Lamps

Fluorescent lamps designed for quick operation, using continuously heated cathodes.

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Instant Start Lamps

Fluorescent lamps that don't preheat their electrodes before operation; need higher starting voltage to initiate discharge.

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Ballast Factor

Measures light output of a lamp-ballast system relative to a standard.

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Energy Efficiency

Measure of how much light a fluorescent lamp produces compared to the power it uses, some power becomes heat.

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Lamp-Ballast System Efficacy

How efficiently a particular lamp type and ballast works together.

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Ballast Noise

Humming sound caused by the magnetic field changes in the ballast core.

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Triphosphor Lamps

Fluorescent lamps with a special coating that reduces light loss over time.

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Fluorescent Lamp Depreciation

Natural decrease in light output over time for fluorescent lamps.

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