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25 Cards in this Set
- Front
- Back
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wavelength
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distance between crests of adjacent waves
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frequency
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number of wave crests that go by a given point every second
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velocity
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speed & direction of the wave crest itself.
= length of each wave x # of waves that pass each second |
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amplitude
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height of wave crest above the undisturbed position (base level)
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Hertz
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cycles / second
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longitudinal waves
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particles that move back & forth in the direction of the wave ("pressure wave")
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transverse waves
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particles that move perpendicular to the direction of the waves
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human perception of sound
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wavelength, frequency, & amplitude
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short wavelength, high frequency
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high pitched sounds
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long wavelength, low frequency
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low pitched sounds
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high amplitude
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loud sounds
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low amplitude
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soft sounds
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humans
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vocal communications; cues about environment
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bats
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high-frequency echo-location (listening for bounced sound waves) to navigate & locate insects/other food
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whales, dolphins, porpoises
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low-frequency echo-location for navigation in sea water
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interference
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waves from different sources overlap & affect one another
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constructive interference
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2 waves from different sources combine to reinforce one another (crests coincide)
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destructive interference
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2 waves from different sources combine to weaken or cancel each other out (crests fall on troughs)
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electromagnetic waves
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waves made up of electrical & magnetic fields that fluctuate together; once the waves starts, it keeps going, even in a vacuum
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Maxwell (1831-1879)
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studied electromagnetic waves.
1. wrote equations on electricity & magnetism 2. predicted speed of light = 300,000 km/sec 3. light & other electromagnetic waves are types of waves that are generated whenever electrical charges are accelerated |
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electromagnetic wave
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consists of electrical & magnetic fields oriented @ right angles to one another & perpendicular to the direction that the wave is traveling
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"The Ether"
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a presumed medium for electromagnetic radiation (thought to fill in open space & convey waves) theorized before the discovery that these waves don't require a medium; shown not to exist by experiments conducted in 1887 by Michelson & Morley
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Maxwell
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velocity of electromagnetic waves depends entirely upon the nature of interactions between electrical charges & magnetic charges, so it can't depend on properties of the wave itself
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speed of light
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speed at which all electromagnetic waves (including light) move, regardless of wavelength or frequency.
c=300,000km/sec |
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energy of wave increases
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with decreasing wavelength
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