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56 Cards in this Set
- Front
- Back
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Pythagoras |
(6th century BC) - light beats from eyes (sight = eye light beans hitting objects) - light travels in straight lines (even as waves) |
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Euclid |
(1st century AD) - relationship between mirrors and light (law of reflection) |
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Al-Haytham |
(100 AD) - accurately describe how eyes function + eye diagram (light bounces off objects to eye - eye ≠ source) - beat commonly accepted idea |
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Ole Romer |
(1676) - reasonable guess at speed of light (though observation of Jupiter’s moons Io’s eclipse arrival time) |
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Sir Isaac Newton |
(~1700) - discovered that white light is actually a mixture of all different colours of light - uses prisms to refract, separate and recombine, white light - described lights impact on colour (all waves except colour perceived are absorbed by object) |
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William Herschel |
(~1800) - (measured temperature of colour/light spectrum and) noticed that there was energy past the visual bar of colour - called discovered energy/part ‘heat waves’ (now known as infrared light) |
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Johann Ritter |
(~1800) - (measured temperature of other side of colour/light spectrum and) noticed that chemical reactions are faster past the violet end - called discovered energy/part ‘oxidizing rays’ (now known as ultraviolet light) |
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James Clerk Maxwell |
(1865) - unified electricity and magnetism into electro-magnetic spectrum/electro-magnetic waves - e-m waves travel at same speed as light - confirmed that light acts like wave, not particle (partially true)
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Max Plank |
(1918) - correct theory about energy across e-m spectrum (that it acts as packets of waves called photons) - combined wave and particle model of light - set stage from quantum theory |
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4 properties of light |
1. (If undisturbed) travels in straight lines 2. Can be reflected 3. Can be refracted 4. Is a form of energy |
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Speed of light |
- 299 798 km/s - always constant (despite medium) |
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Luminous |
Emits viable light |
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Non-luminous |
Doesn’t emit visible light |
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Opaque vs Translucent vs Transparent |
Oq: light fully can’t pass though, casts shadow Tl: light partially passes though, casts vague shadow Tp: light fully passes through, casts no shadow |
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How do we see |
Light is emitted in all directions and reflects off objects to be perceived/focused/processed by the eye |
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Law of reflection |
The angle of incidence (angle of light hitting the mirror to normal line* ) = the angle of reflection (angle of light hitting off the mirror to normal line)
*normal = line perpendicular or mirrors surface that goes from point of contact out |
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Concave mirrors |
- looks upside down past the focal point - looks larger - converges light rays - enlarge image - e.g. telescope |
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Convex mirror |
- bulges out - focal point is theoretical (only exists as perceived behind mirror) - looks smaller - diverges light rays - shrink image (show more area) - e.g. surveillance mirror |
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Refraction |
The bending of light as it passes between mediums*
*medium: any substance |
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Refractive index |
The number that describes the amount of refraction (predetermined values assigned to each medium, then is taken between the two) |
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More dense? |
Smaller angle/angle is more ‘normal’ Explain: the particles slow down in denser mediums |
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Convex lens |
- Converging (opposite with mirror) - Example: Telescopes/binoculars, cameras, flashlights, laser, fix hypermetropia/far sightness (bigger + father away) |
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Concave lens |
- Diverging (opposite with mirror) - Example: sideview mirror on driver side windows, security mirrors in supermarkets, fix myopia/close sightness (smaller + closer) |
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Telescope |
- A type of optical device that functions by magnifying and collecting light - variants = reflect and refract - used for seeing things in space/farther away |
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Reflecting telescope |
- uses mirrors (therefore not size limit, as support from back stays stable) - parts include: objective mirror, plane mirror, eyepiece, - like binoculars ? |
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Refracting telescope |
- uses lens (therefore size limit, as support from sides doesn’t stay stable) - parts include: objective lens, real image, eyepiece, - like microscopes ? |
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Microscope |
- act similarly to refracting telescopes (lens) - used for seeing things up close |
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Binoculars |
- act siilarly to telescopes (just two telescopes together) - benefit is periperhal vision - similar to both type of telescope (refracting/lens/prism) - used to look farther away |
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Ray Diagram |
- used to visualize how light rays move |
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Regular reflection |
- when light reflects off a smooth object, forming a clear image |
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Diffuse reflection |
- when light reflects off a rough object, forming an unlcear image |
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Incident Ray |
the ray of light that makes contact with the lens/mirror |
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Relected Ray |
the ray that is relflected off a surface |
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Angle of Incidence = Angle of Refleciton (t or f) |
rue |
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Focal point |
(theoretical or physical) point in which all the light rays converge in one point ( |
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Wavelength |
- Length between two crests/troughs - longest are after infrared - frequency up = wavelenght down |
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surface vs mirror vs lens |
- surface - on one side - mirror - reflects light well - lens - double lens on both sides |
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Frequency |
- Number of cycles (crest to trought to crest) is in a certain period of time (usually 1 sec) - ultra violet up = more frequecny - frequency up = wavelenght down |
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Crest and Trough |
Crest - Top of wave Trough - Bottom of wave |
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Amplitutde |
The intenstiy/brightness of the light |
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Radio Waves |
- e.g. radios - least dangerous wave length |
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Microwaves |
- e.g. wifi, cellphone, cooking, etc. - second least dangerous wave length |
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Infrared Radiation |
- e.g. tv remote control, hear (from sun) - emits heat! |
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Visible light |
- colours of the rainbow (overally ROYGBV) - order = : - longest wavelength to shorest wavelength - least danger/enerby to most danger/energy |
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Ultraviolet radiation |
- e.g. hospitals, sunburn, sterilization - some animals can naturally see UV light |
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X-rays |
- travels through soft tissue (but not hard ones, like bone) |
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Gamma-rays |
- most dangerous to body - uesd in nuclear work (created nuclear weapons/factories, etc.) |
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Colour legend |
Primary = Red (r), Green (g), Yellow (y) White = all in equal Black = all in not equal Magenta = r + g Yellow = b + r Cyan = g + b |
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Cornea |
Transparent layer at front of the eye |
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Iris |
The coloured part of the eye |
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Pupil |
The entry point of light to the eye |
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Lens |
a part of the eye that refracts light entering to focus it |
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Retina |
The back of the eyeball (contains the optic nerve, rods, cones ) |
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Optic Nerve |
The nerve that connects the brain the the eye and processes information |
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Rods |
The cells that detect the intensity of light |
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Cones |
The cells help dictate colour (with theree types of cones RGB) |
