In physics, interference is a phenomenon in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude. Constructive and destructive interference result from the interaction of waves that are correlated or coherent with each other, either because they come from the same source or because they have the same or nearly the same frequency. Interference effects can be observed with all types of waves, for example, light, radio, acoustic, surface water waves, gravity waves, or matter waves. The resulting images or graphs are called interferograms.
Homework Statement
http://img5.imageshack.us/img5/4605/lchuynh177setphys52awee.png
The figure shows the interference pattern that appears on a distant screen when coherent light is incident on a mask with two identical, very narrow slits. Points P and Q are maxima; Point R is a minimum...
Homework Statement
A very thin sheet of plastic (n=1.70) covers one slit of a double-slit apparatus illuminated by 630 nm light. The center point on the screen, instead of being a maximum, is dark. What is the (minimum) thickness of the plastic?
Homework Equations
Constructive...
Homework Statement
A source emits pairs of particles "back to back", 50% into directions a1 and b1, 50 % into directions a2 and b2, where the choice between a1+b1 and a2+b2 is fundamentally undetermined.
Insert Diagram A
suppose that directions a1 and a2 are combined on a 50/50 beam...
Homework Statement
8 bright fringes are counted across 1.06 cm in the air wedge.
Homework Equations
Δx = L (λ/2t)
The Attempt at a Solution
i don't understand whether Δx is:
8Δx = 1.06cm
or
7Δx = 1.06cm
it said 8 bright fringes but Δx = the distance between...
I have a confusing question mainly due to my lack of understanding of Quantum Mechanics and spin! here it goes anyway...
In an atomic orbital, like the 1s orbital, two electron waves with opposite spins occupy the same area of space. Now, does this mean that their waves should interfere with...
Homework Statement
A glass-plate of 350 nm thickness is free standing in space. At the angle of 75 degrees, relative to the glass-plate plane, a white light point-source is placed. The diffraction (probably a typo, and should really be refraction) index of the glass is 1.33. On the same side...
Homework Statement
What are the values of incomplete destructive and constructive interference?
Homework Equations
The Attempt at a Solution
when the path difference is in between 1 wavelength and 0.5 wavelength, there would be "incomplete" destructive interference. From my...
Not sure whether to put this in the QM forum or the classical forum, you'll see why--
I was thinking about the http://grad.physics.sunysb.edu/~amarch/ version of the double slit experiment, in which the information about which slit the particle went through is obtained in a somewhat unusual...
I am trying to play a movie from my macbook pro with the video to a standard HD tv and the audio to a guitar amplifier.
I connected the guitar amplifier to my macbook pro through a 1/4" to headphone jack cable and the sound outputted to the amp was fine, just as I wanted it. As soon as I...
hi everyone,
i was wondering whether i can change this sentence ( if the phase difference changes rapidly , the average effect of no interference is recorded.) to( if the phase difference changes rapidly , the average effect of no superposition is recorded.)
as i remember that the term...
I put together this little movie as (hopefully) the first in a series.
http://www.youtube.com/watch?v=xjMjWtntm9k"
My target audience is a second semester class of physics students that have already had a lectures in basic wave optics. When I give this URL to my students, it's with the...
5. Two slits are separated by 0.195 mm. An interference pattern is formed on a screen 33.0 cm away by 656.3-nm light. Calculate the fraction of the maximum intensity a distance 0.600 cm away from the central maximum.
d =.000195m
L = .33 m
lambda = 656.3 nm
y = .006m
it's a small angle...
Homework Statement
"Light is incident from above two plates of glass separated on both ends by small wires of diameter d = .6um. Considering only interference between light reflected from the bottom surface of the upper plate and light reflected from the upper surface of the lower plate...
I know about the law of conservation of energy, and I understand interference effects conceptually, but when I put the two together I'm a little confused.
I know that the energy of light must simply by transformed in destructive interference...but where does it go and how?
If the...
Homework Statement
Light of wavelength 470 nm passes through a block of material with a refractive index n = 1.30, some of it is reflected off the air-block boundary and some of it is transmitted through air (n=1.00) with thickness t, and is then reflected off another block also with n = 1.30...
Hi,
I am new to QM and really confused with some concepts.
Assume two alpha particles come out from two different sources and reach the same detector, so the probability to detect some particles should be |f+g|^2 (f, g are the amplitude of 1st and 2nd alpha particle, respectively). If they are...
Homework Statement
Write a wave in one space dimension as ARe(ei(kx-wt-d))where A is the
amplitude of the wave. Find a second wave of the same frequency such that
the sum of the two vanishes at x = 0 and x = L. Assuming the wave velocity
c = w/|k| is fixed, for what frequencies ! is this...
I have followed some of the previous posts on the topic , but the conflicting arguments have left more than confused. Consider this simple scenario : Two wave pulses on a string generated by identical sources but with a phase difference of 180 degrees meet and interfere destructively. For...
Okay, I have this problem worked out, but I have no clue if my answers are right. Could someone please check my work and give me some confidence or show me where I may have messed up.
Homework Statement
Two loudspeakers, one of them generates sound with 400 W power the other with 100 W. The...
Homework Statement
Two speakers located 4.0 m apart. Listener is seated 25.0m from 1 speaker, and 27.0m from the other. We drive the two speakers at a freq. which we sweep from 100 to 500 Hz. If the 2 speakers are in phase, find the frequencies at which the waves constructively/destructively...
Homework Statement
A 4-slit interference pattern is created by 4 slits spaced 2μm apart. At what approximate angle θ does the intensity go to zero the first time, if the incoming light has a wavelength of 450 nm?
θ1st min =
Homework Equations
d*sinθ = m\lambda
The Attempt at a...
What does it mean physically when radio stations mix? As in if you are listening to one station, but you begin to here another and eventually only here the wrong station.
Hi,
Two loudspeakers are connected to the same audio oscillator. An observer walks in between them. At a point M, halfway between the speakers he hears a loud sound. By the time he gets to a point P 2m away from M he hears no sound at all. Calculate the maximum wavelength of sound emitted by...
Hello,
was wondering a couple of details on the wave nature of electrons and the state of the art in this field. In particular:
Is it practical and possible (easily) to create a cm sized electron interference pattern (fringes are in the cm size magnitude). I have so far seen Low Energy...
I have two questions concerning what happens when light interference occurs.
In destructive interference of coherent light beams, how is energy conserved, both when interference occurs in air and in a vacuum.
When non coherent light beams intersect is space there is no interference...
Hello
In my textbook There are two headlines "Superposition" and "interference
but I can't recognize any difference between the two terms
So what is the difference between them?
Thanks
If you have a 3 phase 4 wire distribution where the 3 phase conductors and 1 neutral is inside a pvc conduit, how would you model the force of the electromagnetic field at a certain distance away from the conduit?
Assuming the loads are balanced, the currents would sum to zero on the...
Hi,
Question: X and Y are two identical sources of sound which emit in phase. Calculate the lowest possible value of frequency of the sources for there to be (a) constructive (b) destructive interference at Q.
So, X is at 1.8 m from Q and Y is 1.2 m away from Q.
a) If they leave in...
Hello, this is my first visit to PF. I have a question that I can tell isn't very difficult, but I can't seem get my head around it, maybe i just need to review my text and make an attempt tomorrow.
Homework Statement
Consider the point P in the following diagram. Analyze this diagram to show...
Suppose you have two coherent microwave beams, one beam at 45 degrees to a reflecting wall and the other one at 90 degrees, with the two beams pointing to the same point on the wall.
If the two beams are 180 degrees out of phase and destructively interfere at the point on the wall, will the...
Can anyone break down "quantum interference" in the tunneling transport through aromatic organic molecules? The Math is a little fuzzy, but with a few seminal reference or a conceptual description i might be able to wrap my mind lips around this knowledge pop! haha. any help would be appreciated.
Homework Statement
We have a thin film of glass which has thickness t=\lambda and n=1.5 and light (\lambda) passing through it with an angle \theta_0.
We have to find the minimum angle that allows us to see both constructive and destructive interference.
Homework Equations
Max...
Homework Statement
I've been reading a book about waves. I skipped the test earlier this year because I had not done any problems and thought it would be a waste of time to try. But now I kind of have to do it, I've re-read the book but it's much to understand and remember.
Especially the...
Look at the picture below, I have to prove that the optical path length difference is
\Delta=n(BC+CD)-BE=2nd\cos(r)
[PLAIN]http://img200.imageshack.us/img200/2271/schermata082455775alle1.th.png
The problem is just how to get 2nd\cos(r)
I actually don't have any idea :\
I have...
Hello, I am trying to understand thin film (in air) interference but I have a problem:
I know we have destructive interference when \delta=(2m+1)\pi.
Now i can try to calculate the thickness of the film to get it, so
since \delta =\frac{4nt\pi}{\lambda} - \pi where t is the thickness...
Two radio antennas A and B radiate in phase. Antenna B is a distance of 130 m to the right of antenna A. Consider point Q along the extension of the line connecting the antennas, a horizontal distance of 50.0 m to the right of antenna B. The frequency, and hence the wavelength, of the emitted...
Right so I've been stuck with this for a while now and I'm sure it's just something simple that I've missed. Right so the question says there are a pair of closely spaced slits (0.300mm apart). By changing the spacing the bright fringe moves from position m=2 to m=3. The wavelength remains...
For example, when two light waves completely cancel each other out, there is the black on an interference pattern, indicating absence of light.
What happens to the photons? It seems they cease to exist.
Also, How does this relate (or not) to the "Conservation of Energy" law?
Any...
Homework Statement
A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 53.2 m apart. The speakers emit sound at a frequency of 459 Hz. At the midpoint between the speakers, there will be...
I have only an completed one course on quantum mechanics so please excuse me if this seems rudimentary.
In my course we only dealt with electrons and their interference with one another. Is it possible for an electron and a proton to interfere with one another? Or more generally, can...
Homework Statement
At a young's experiment arrangement, there is a 500nm light beam, a distance of 1m from the slits to the screen and a 0.25mm between the two slits
In what way the interference pattern will change if an adhesive tape is being taped to one of the slits with a 1mm thickness and...
Can someone explain what the difference is between the expectation value of an observable in a pure vs a mixed state. The equations are identical. For example with spin up and down |A|^2<S_u|O|S_u> + |B|^2<S_d|O|S_d>
In the paper (AIP Conf. Proc. 810 (2006), 360):
Mardari outlines three predictions of quantum self-interference, all of which empirical evidence is presented that appear to refute all three. The implications of the paper is interesting but of these I am particularly interested in the...
"consider the same interference experiment,the interference pattern produced is used to illuminate the next source in series,which then produces a new interference pattern,this gets cascaded say 10 times and the final interference pattern is obtained on the wall.
now ,the observer, observing...
Homework Statement
A beam of electrons is accelerated from rest and then passes through a pair of identical thin slits that are 2 nm apart. You observe the first double-slit interference dark fringes occurring at ±20◦ from the original direction of the beam when viewed on a distant screen.
(A)...
Hi,
I was wondering if two waves, whom both have the same frequency and wave, could be combined together in a constructive interference way, even if they did not have the same amplitude?
Homework Statement
In a large water tank experiment, water waves are generated with straight, parallel wave fronts, 3.0m apart. The wave fronts pass through two openings 5.0m apart in a long board. The end of the tank is 3.0m beyond the board. Where should you stand, relative to the...
in DCQE you can get which way and still get interference?
for example when the s-photon strikes the detector ...let's assume setup is such that which-way is known
now we send the idler via erasure (after registration of s) and later when we sub-sample via co-incidence counting we get...