Wave Phenomena Flashcards
(23 cards)
Doppler Effect
Apparent change in frequency of a wave due to the relative motion between the source of the wave and the observer of the wave
Source Moving Towards
Waves per second- more
Frequency- higher
Wavelength- shorter
Amplitude (volume) - increases
Speed- same
Source Moving Away
Waves per second- fewer
Frequency- lower
Wavelength- higher
Amplitude (volume)- decreases
Speed- same
Observer Moving Towards
Waves per second- more
Frequency- higher
Wavelength- same
Amplitude (volume)- increases
Speed- higher
Observer Moving Away
Waves per second- fewer
Frequency- lower
Wavelength- same
Amplitude (volume) - decreases
Speed- lower
STS and OTA
Source Towards Subtract
Observer Towards Add
Percent change in frequency
Change in frequency / real frequency
When finding wavelength with perceived frequency…
Make sure to add the speed of the observer and the speed of the sound for “V”
Redshift and Blueshift
Redshift- “RED RUNS AWAY” wavelength increases, away from earth
Blueshift- “BLUE COMES TO YOU” wavelength decreases, comes towards earth
Diffraction
Bending of a wave around a barrier or spreading through an opening
-More diffraction with longer wavelengths and shorter openings
-Just changes direction of wave (not frequency, speed, etc)
-Sound diffracts a lot bc it has large wavelength (compared to light)
Law of Reflection
the angle of incidence equals the angle of reflection
Refraction
A change in direction, or bending of a wave, at the boundary between mediums
-Caused by a change in speed
-Only happens when a wave hits the boundary obliquely (at an angle)
Refraction Rule
FAST
-faster medium, away from normal line
-slower medium, towards normal line
Absolute Index of Refraction (n)
The ratio of speed of light in a vacuum to the speed of light in a material medium
Relationship btwn speed and index of refraction
Inverse
Snell’s Law
Allows us to find the angle of incidence or refraction of light waves traveling from one medium to another
Dispersion
The separation of white light into different color rays
Dispersion rule
Blue Bends Best (but violent bends better)
-Each frequency has a lightly different index of refraction, and higher frequency bends the most
Violet: high n, slowest, bends the most
Red: low n, fastest, bends the least
Critical Angle
The incident angle unique to a substance that causes the refracted ray to lie along the boundary of the substance (refracted ray is 90)
-Must be more dense to less dense
sin Θc = 1/n
Total Internal Reflection
Occurs when light is incident on the boundary to a less optically dense medium ant an angle so large there is no refracted ray
-More dense to less dense
-Angle has to be greater than critical angle
Double Slit Experiment
-Shows how light is like a wave and allowed us to calculate light’s wavelength
-bright spots are constructive (0 phase difference), dark areas are destructive (180 phase difference)
Number of slits increases…
-Bright fringes become sharper/narrower
-Faint bright fringes appear within the dark fringes
Diffraction grating
A piece of glass or plastic with many equally spaced parallel slits on it
d=1/N
(N is the number of slits, d is the spacing between them)
