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13 Cards in this Set
- Front
- Back
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define light and it's properties |
light is a source of energy and it Travels in waves. light has diffarent colours and different colours of light have diffarent amounts of energy |
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define a light source and examples |
a light source is an object that can give of its own light examples are natural- sun , lightning , spark , flames. creatures- glow worms and fire flies chemicals such as phosphorus man made - light bulb metal such as molten |
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define detectors of light and give example |
a light detector is an object or substances that detect light or changes when light is present. examples eyes or cameras or chemicals such as silver chloride anf light meters |
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define an illuminated and I luminous |
illuminated- can't radiate it's own light only reflect light that shines on them luminous objects- radiate there own light |
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define transparent and opaque objects |
transparent objects objects through which other objects can be seen clearly and transmit light opaque- don't transmit light |
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define a light ray and light beam |
a light ray is a line representing the direction light is being propagated a light beam a stream of light energy represented by light rays |
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define a parallel beam |
light rays that remain equidistant from each other |
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define a convergent and divergent beam |
a convergent beam us a beam of light rays that move towards a point a divergent beam is a beam of light rays that move away from a point |
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define the rectilinear propagation of light |
it means light travels in Straight lines and is the formation of shadows |
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define reflection and the process |
reflection is the bouncing off of light particles. from a light source light hits the surface as the incident ray and is reflected by the surface as the reflected ray. the incident point is where the incident ray meets the reflecting surface. the normal is the perpendicular line to the surface at the point of incidence. then you get angle of incidence and reflection |
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law of reflection |
the angle of incidence is equal to angle of reflection |
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define absorption of light and process |
when light strikes an object and does not leave the object. 1. white hits a dull black surface no light is transmitted because all the light was absorbed. this applies to all black surfaces 2. when white light strikes an opaque red paper. red light is reflected because the paper absorbed all colours except red. 3. when red light strikes a opaque red paper red light is reflected 4. when green and blue light strike an opaque red paper no light is reflected because the red paper absorbs all colours but red. |
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define refraction of ligh |
the change in direction of light when it Travels from one optical medium to another optical medium. light changes speed when it Travels through an optical medium with diffarent density. glass has the greatest optical density. when light enters a more dense optical medium it's refracted towards the normal. it's refracted when it enters an interface between two media if they have diffarent optical density at an angle and occurs at the interface. |
