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24 Cards in this Set
- Front
- Back
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what is the crest of a wave? |
-is the highest point on the wave |
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what is awavelength? |
length of a full cycle of a wave |
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what happens when wave hits boundry full on? |
if light wave hits boundry face on - it slows down in same direction. now it has a shorter wavelength but same frequency |
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what is diffraction? |
is the spreading out of a wave as it passses through a gap |
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explain diffraction sizes of gaps |
-larger gaps show less diffraction |
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what is the amplitude? |
displacement from the rest position to crest |
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what is the frequency? |
- number of full cycles passing a certain point.per.second |
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when a beam of light reflects of even surface, what happens? |
when a beam of light reflects of a even surface, light reflects off at different angles |
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when light reflects of a EVEN surface? |
reflects at same angle |
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ANGLE OF INCIDENCE = |
= ANGLE OF REFLECTION |
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When does total internal reflection happen? |
only happens when light rays travel though a dense material ---> less dense |
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is angle incidence is less than critical angle ... |
..most of light is refracted into outer layer bu ut some internally reflected |
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if angle of incidence is = critical angle |
ray goes along surface , bit of internal reflection |
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what is refraction? |
- when a wave crossesa boundry between 2 substances- it changes speed |
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what happens when wave meets a different medium at a angle? |
different median at angle = wave changes direction |
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what happens when wave travels along normal? |
if wave travels along the nrormal - wave changes speed, no refraction |
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diffraction if gap is much wider than wavelength? |
gap wider than wavelength then little diffraction |
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diffraction gap the same as wavelength? |
lots of diffraction |
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what does diffraction cause? |
reduces quality of images seen in microscopes and telescops causes rings and spikes around image |
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1 KHz = |
1000 Hz |
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1 MHz = |
1,000,000 Hz |
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if angle of I is GREATER than critical angle ... |
...then no light coms out, all light internally reflected |
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diffraction gap abit wider than wavelength= |
= diffractin at edges |
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why can we hear somoene through an open door even though we cant see them? |
-because size of gap and wavelength of sound are rougly equal causing sound wave to diffract and fill room - but you cant see them unless youre facing them because gap is about millin times bigger than wavelength of light so wont diffract enough |
