Periodic Motion Flashcards
constructive interference
-Waves are additive producing a louder or brighter spot
-A crest lines up w/ a crest or trough w/ a trough
destructive interference
Waves completely cancel each other (quiet/dark spot)
-A crest lines up with a trough
Constructive interference equation
∆r = (m)λ
∆r is the path length difference |r1 - r2|
Destructive interference equation
∆r = (m+ 1/2)λ
∆r is the path length difference |r1 - r2|
Destructive interference is anything 0.5, 1.5, 2.5 etc
Interference, whether constructive or destructive affects (amplitude/wavelength).
Amplitude which directly affects intensity
A proportional to I^2
Diffraction
When light passes through a narrow opening, light waves spread out
Diffraction through a single slit produces a pattern of dark & bright bands. Destructive interference causes (light bands/dark bands).
Dark bands because the two waves cancel out, causing no light.
How does the width of the slit (that light passes through) affect the band pattern?
As slit width increases, distance between the dark & light bands decreases
Relationship between wavelength and distance between dark & light bands
As wavelength of incident light increases, the distance between dark & light bands increases too
single slit diffraction
sinθ = mλ/a
m is an integer indicating the # of the fringe
λ wavelength of the incoming wave
θ is angle between the line drawn from the center of the lens to the dark fringe
double slit diffraction
Light is shown through 2 slits
equation: dsinθ=(n+1/2)λ
d is distance between 2 slits
θ is angle between the line from midpoint of the 2 slits to the dark fringe and the axis of the lens
n indicates number of the fringe.
λ is incident wave
For double slit diffraction, as the two slits move further apart from each other
The distance between the fringes become closer together.
