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53 Cards in this Set
- Front
- Back
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Frequency
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The rate of repitition of a wave.
OR the number of times that a wave (crest) passes a stationary point over a period of time. --> Expressed as cycles / time (secs or mins) |
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Crest
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The highest point in a wave
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Trough
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The lowest point in a wave
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Rest Position
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The level of water without waves
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Wavelength
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The distance between 2 similar points in a wave
---> Crest to crest / Trough to trough) |
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Amplitude
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The distance from rest position to crest or trough
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The number of waves are called...
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Cycles
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Formula to calculate the speed of a wave
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v= f x λ
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Light is a form of ...
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energy
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Electromagnetic radiation
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A wave pattern made of electric and magnetic fields hat can travel through empty space
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Radio Waves Definition
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- Longest wavelength
- Lowest Frequency - Used to carry information around the world |
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Microwaves Definition
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- Shorter wavelengths than radio waves
- Carry more energy than radio waves - Have a higher frequency |
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Infrared Waves Definition
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- Shorter wavelengths than microwaves but longer wavelengths than light waves
-Higher frequency than microwaves - Experienced as heat - Images are called thermograms |
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Ultraviolet Rays Definition
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- Carry more energy than visible light
- Have a shorter wavelength - Higher frequency than visible length |
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X- Rays Definition
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- Very high energy radiation that can penetrate human tissues
- Difficulty passing through bones (gets reflected) - High frequency and shorter wavelengths |
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Gamma Rays
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- Extremely high energy radiation
- Very high frequency and very short wavelengths |
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Visible Light
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- Energy made up of 6 colours (ROYGBV) and travels in waves
- Found between infrared waves and ultraviolet rays in the electromagnetic spectrum |
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Radio Waves Life Examples
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- Radio communications (Mines, submarines, and aircrafts)
- Television signals, cell phones, satellite communications, internet - MRI scanners used to see soft tissue and organs visible |
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Microwaves Life Examples
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- Microwave Ovens
- Radars - Monitor Aircraft flights - Map earth and other objects |
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Infrared Waves Life Examples
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- Thermograms
- Burglar alarms - Motion sensors - Night vision goggles - Devices that keep food warm in fast food restaurants -Toasters |
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Ultraviolet Rays Life Examples
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- Naturally occurs in the sun and other stars
- Beneficial to human health as long as there is no extended exposure - Used to disinfect drinking water - Used in DNA analysis |
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X-Rays Life Examples
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- Medical imagery
- Security measures to scan luggage at airports - Photography of the inside of engines, pipelines, and other machines to check for fractures or damage |
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Gamma Rays Life Examples
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- Sterilizing medical equipment
- Doctors use short bursts of gamma radiation from different angles to kill cancer cells - Produced naturally by phenomenons such as neutron stars and black holes |
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3 Primary Colours of the Additive Theory
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RED
GREEN BLUE |
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Blue + Red = ....
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Magenta
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Red + Green = .....
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Yellow
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Blue + Green = ....
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Cyan
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Red + Green + Blue = .....
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WHITE
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Complimentary colours are.....
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Secondary colours to the primary colours
(Opposite of a primary colour) |
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3 Primary Colours of the Subtractive Theory are....
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Cyan
Magenta Yellow |
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Yellow + Cyan = .....
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GREEN
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Yellow + Magenta = ....
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Red
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Cyan + Magenta
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Blue
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White - Green - Blue - Red =....
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No light
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Yellow + Magenta + Cyan = .....
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BLACK
---> Since all the colors are absorbing themselves |
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Transparent
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Clear light passes freely
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Translucent
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Transmitting some light but not enough to see through clearly
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Opaque
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Objects absorb and reflect light but they do not transmit as shown
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Light Travels in...
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Straight lines
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How is the brightness of light influenced by your distance from the light source
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The more rays reaching the eyes makes the light seem brighter and the fewer light rays reaching the eyes when your are further away makes the light seem not as bright.
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Umbra
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The part of a shadow in which all light rays from the light source are blocked
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Penumbra
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The area of partial shadow from a non point light source
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Bioluminescence
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The ability of a plant or animal to produce light
---> Light is used to find prey, scare off predators, attract mates, or to camouflage themselves ---> 90% of all sea creatures are bio-luminescence EXAMPLES: Fireflies, angler fish, algae, and jellyfish |
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Incandescent Light
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Light that is produced by an object such as metal, hat is at a very high temperature
---> Electric current flows through the filament heating it to an extremely high temperature ---> 95% wasted as heat and 5% converted to light energy EXAMPLES: Incandescent light bulbs |
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Fluorescent light
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Light emitted by some substances when they are exposed to electromagnetic radiation
---> 20% electricity converted to light energy and 80% wasted as heat ---> Electric current energizes the atoms in the gas (mercury vapour) -> emits ultraviolet radiation -> strikes the phosphor powder which the glows and emits lights EXAMPLES: Compact fluorescent bulbs and fluorescent light tubes |
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Phosphorescent Light
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Storing energy form a source of light then emits slowly over a long period of time.
---> phosphorescent materials glow in he dark for some time after being energized by light ---> Can be re-energized if the object is held close to a light source for a few minutes EXAMPLES: Any glow in the dark object |
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Chemiluminescence
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Light produced from a chemical reaction without a rise in temperature
---> Light is sometimes referred to as cool light ---> All forms of bioluminescence are special kinds of chemiluminescence EXAMPLES: Glow Sticks and Luminol |
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Triboluminescence
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Producing light from friction.
---> Some crystals can be made to glow simply by rubbing them together or crushing them. EXAMPLES: Quartz rattles and biting down on a wintergreen mint |
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Electric Discharge
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A method for producing light in which an electric current passes rough the air or another gas.
---> Carbon-arc light sources can be used to produce searchlights powerful enough to reflect off clouds EXAMPLES: Lightning, neon signs, and sodium gas street lamps |
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Light Emitting Diode (LED)
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An electroluminescent light source made out of a small material called a semiconductor.
---> Very efficient emits light with a small electric current ---> Uses electroluminescence the process of transforming electrical energy directly into light energy ---> Solid, Durable, and gives off very little heat EXAMPLES: Billboards, Traffic Lights, Decorative lights, handheld displays, Automotive lights |
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Organ Light-Emitting Display (OLED)
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A light source made up of several extremely thin layers of organic molecules that use an electric current to produce light.
---> Thinner, lighter, brighter, and more flexible, ---> Can be rolled up or embedded in fabrics or clothing EXAMPLES: Cellphones, medical equipment, head mounted displays, large television displays, and computer screens |
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Plasma Display
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Each colour is a tiny fluorescent light in which an electrical signal causes a gas, such as neon, to release ultraviolet radiation
---> Ultraviolet radiation is absorbed by phosphors that then radiate light in the visible spectrum - Different phosphors used to produce red, green, and blue light EXAMPLES: TV's |
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Liquid Crystal Displays
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A white light, such as a fluorescent light or light emitting diode shines behind a liquid crystal.
---> Red, Green, Blue, filters are placed in front of the crystal to produce colours ---> The white light that shines behind the crystals is always on EXAMPLES: Laptop computers, digital watches, cell phones, iPods, and many flat panel TV's |
