Wave 2 Flashcards
Principle of superposition of waves
when two waves meet at a point the resultant displacement is at that point is equal to the sum of individual waves
coherence definition
waves emitted from two sources having a constant phase difference
in order to have that they must have the same frequency
how much path difference for maxima and minima
maxima occurs when they are nλ waves length apart, where n is any integer
minima occurs at nλ, where n is a odd number
double slit wavelength and distance to first maxima equation
λ = ax/D
λ = dx/D
a = d, they are both the slit separation
d «_space;D
Formation of Stationary wave
two porgressive waves of the same frequency travels in opposite direction are superposed.
https://www.desmos.com/calculator/b7kxqry7xe
nodes and antinodes
points where the displacement of the stationary waves always 0 (given both waves are of the same amplitude)
antinodes are points when the waves are always in phase - points of the greatest amplitude and therefore intensity
equation for path differnece of waves in a 2-slit
and condition for maximas
path difference = d sinθ
where θ is the angle of the beam to the normal
d is the slit separation
mλ = dsinθ
where m (for maxima) is any integer
λ is the wavelength
phase difference along a stationary point
in between two adjacent nodes all particles in a stationary wave are oscilating in phase. however, their amplitude differ.
comparing stationary and progressive waves
energy transfer
s:
no net transfer
p:
in the direction of travel
wavelength:
s:
twice the distance between adjacent nodes/antinodes is the wavelength of the progressivewave that created teh stationary wave
p:
minimum distance between two adjacent points oscilating in phase, eg peak and peak
phase difference:
s:
all parts of the waves between two adjacent nodesare in phase, different sides are in antiphase.
p: changes across one complete cycle of the wave
amplitude:
s:
maximum amplitude occurs at antinode and drops to zero at the node
p:
all parts of the wave have the same amplitude (assuming no energy dissipation)
forming stationary wave using microwaves
reflecting a microwave emitted from a microwave transmitter off a metal plate. in the middle there’s a microwave receiver which will detect the changes in the intensity between the nodes.
distance between the transmitter is adjusted until receiver detects a series of nodes and antinodes.
distance between two sucessive nodes is λ/2
what happens when a string is plucked
it vibrates in it’s fundamental mode of vibration
what is the fundamental mode of vibration
the frequency of this vibration is the fundamental frequency which (for a string) depends of string’s mass tensiona and length
what’s the fundamental frequency
the minimum frequency of a stationay wave for a string,
the string can form other stationary waves called harmonics at higher frequencies
for a string at a fixed tension, what happens when you increase the frequency
teh speed of a progressive wave along the string is constant
v=fλ
frequency increases the wavelenth must decrease in propotion
Melde’s expereiemnt
vibration generator is used to change the frequency on a string, which can be attached to a fixed end or a pully with weights
stationary waves only form whe generator is set to integer number of the fundamental frequency
