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33 Cards in this Set
- Front
- Back
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what is light?
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light is a form of energy
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what is a luminous object?
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is an object that does make its won light and is easy to see. e.g a light globe, the sun.
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what is a non-luminous object?
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it is an object that does NOT form its own light but reflects it. e.g tennis ball, table.
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how do you see an image:
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you see an image when light reflects of your pupil and forms an image on you retina
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when does light change direction?
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when it reflects or refracts
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what is reflection?
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reflection creates the image you see from smooth surfaces. reflection changes the direction of light always making the angle of light the same before and after reflection.
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what is the law of reflection:
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angle of incident = angle of reflection
or I = R |
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these angles are always measured from the ____ that is __degress _________ to the smooth surface or mirror.
complete the sentense |
these angles are always measured from the NORMAL that is 90 degress HORIZONTAL to the smooth surface or mirror
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diagram of a light ray reflecting
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onenote
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can light travell through trasparent objects? examples
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yes, e.g. water, air, glass, perspex, diamonds
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what is refraction?
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refraction is the beding of light.
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when does refraction occure?
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it occures when light travels through a trasparent substamce and the light bends to change direction.
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why does refraction happen?
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this happens because the sppen of light changes as it goes through 1 transparent substance to another.
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where is refraction measured from and what are its angles called
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its measure from the normal
its angles are: - angle of incidence -angle of refraction |
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draw a diagram of refraction
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onenote
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what does the speed of light through a transparent object depend on?
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- how optically dense it is
- what is its refraction index |
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what happens when light enters an optically more dense substance?
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slows down and beds towards the normal
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what happens when light hits a less optically dense substance?
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speed up and bend away from the normal
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what is the refraction illusion
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causes things to appear bent when in water
makes water seem shallower that its actual depth |
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diagram of refraction ilussion
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onenote
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what is total internal reflection?
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when light doesnt refract it skims the boundry of surfaces and cant escape, so it refracts back into the substance
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when does this hapen?
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when the light ray and the normal are greater than the critical angle
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what are lenses?
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lenses are curved pieces of glass that are used to refract to control light and form images in optical instruments.
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what are some optical instruments?
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-telescope
-microscope -binoculars -cameras -specticals |
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what are the two lenses called?
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convex and concave
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what are the difference between the lenses?
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convex- fatter in the middle
concave thinner in the middle |
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what is the principal axis?
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a line drawn directly through the centre of th lense
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what is a principal focus?
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a point were light rays shine parallel to the principal axis focusng in some way.
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focal length?
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the distance between the plane of the lense and the principal focus. the greater the curvnent of the lense the moreit bends light,
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whats the difference between a real and virtual image?
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real- is when light rays cross they can be captured on paper so you can touch them
virtual- cant be captured, they also dont have any light rays passing through them instead light rays are etended. |
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what are the 6 terms for describing an image?
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- enlarged
-diminished - virtual -real -upright -inverted |
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how do you find the magnification of an image?
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sizze of image divided by size of object
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how can you tell if its enlarged or diminished
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if the image is a whole number its inlarged
if its a fraction its diminished |
