Tagged Questions

Waves are disturbances that propagate throush space and time. Classically, they travelled through a medium, disturbing the particles but not changing their mean position. Electromagnetic waves/particle-waves need no medium; they are disturbances in their respective fields.

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52 views

What is matter made of in the light of Quantum Mechanics? [on hold]

I've always wondered what matter (particles, force particles, etc.) was actually made of considering the fact that quantum mechanics has shown us that particles can actually act as a probabilistic ...
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1answer
18 views

Does the equation for a wave passing through two slits apply for particles as waves?

The standard equation for a wave travelling through a double-slit apparatus is $w=\dfrac{z\lambda}{d}$, where $w$ is the fringe spacing at the detector screen on the other side of the slits, $z$ is ...
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1answer
20 views

Direction of the particle's motion

^ y | | |--------------> x Above I have labelled the axes of the graph. In the figure we can see that the direction of the particles motion is downward ...
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0answers
34 views

Fluctuation Dissipation Theorem [on hold]

I take this course at university called Waves and Optics, and a few lectures ago our teacher talked about the Fluctuation Dissipation theorem but I didn't really understand it. The math behind it is a ...
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2answers
21 views

Negative frequency contributions for very short pulses?

I am wondering if very short optical light pulses can have a Gaussian envelope? When I describe the pulse shape with a Gaussian than the frequency distribution has also a Gaussian shape. But if the ...
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3answers
39 views

Derviation of group velocity

I am working thru a derivation of the group velocity formula and I get to this stage: $$y=2A\cos(x\frac{\Delta K}{2} -t\frac{\Delta \omega}{2})\sin( \bar k x-\bar \omega t)$$ Then all the derivations ...
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1answer
29 views

Wavefront sensor specifications Shack-Hartmann

Why is the dynamic range of Shack-Hartmann wave-front sensors (As seen in the first image below) quoted in wavelengths and not in angles? I thought that one of the most important aspects of the ...
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0answers
17 views

Direction of particle's vibration.

I have seen a question related to the the direction of the vibration when a wave moves. I see there two opposite picture that represents contradictory notion of getting the accurate direction of the ...
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2answers
56 views

Electric and Magnetic field's phase difference shift in linearly polarized electromagnetic waves

I am a high school student and we currently studying the electromagnetic theory. In my textbook i read that the oscillating electric the magnetic fields have phase difference equal to π/2 rad near the ...
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0answers
34 views

Derivation of wave-velocity from a wave-equation [on hold]

I am asking for a derivation of the wave-velocity $c$ in terms of the compression modulus $K$ and the density $\rho$. The basis for the derivation should be the acoustic 2-way wave-equation in a ...
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1answer
47 views

Is it possible to use “negative sound waves” to “cancel out” a sound to create silence?

I saw youtube videos that claimed to do this, although I'm quite certain the videos just excluded sound and lied. However, I am wondering if the physics of this is actually possible - to create a ...
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0answers
29 views

can there be an object which reflects( not illuminates ) electromagnetic waves in the non visible region? [closed]

can there be an object which reflects( not illuminates ) electromagnetic waves in the non visible region? If so then will it be appeared to us(humans who can see visible region only) transparent or ...
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2answers
24 views

Wave displacement with phase difference 180

The variation with distance x along a wave of its displacement d at a particular time. A second wave has the same frequency and speed as the wave shown in Fig. 2.1 but has double the intensity. The ...
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1answer
42 views

Speed of sound and Break the sound barrier

What happens when plane exceeds the speed of sound? and What is the interpretation of the conical shape that appears behind the plane?
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1answer
49 views

Diffraction to be explained without Huygens principle

Can we explain diffraction without using Huygens principle?
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0answers
11 views

Relation between size of obstacle, wavelength and diffraction

"If the boundary is merely an obstacle implanted within the medium, and if the dimensions of the obstacle are smaller than the wavelength of the wave, then there will be very noticeable diffraction of ...
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0answers
14 views

What equation can be used to solve an ideal string/membrane in a non-vacuum medium?

I'm interested in the eigenmodes of the membrane for various mediums, such as vacuum, air, water, etc., which impose a damping effect on the membrane. This cannot be done by merely changing the value ...
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0answers
22 views

Difference b/w angular width and linear width of fringe

In double slit experiment and single slit experiment what is the difference between angular width of fringe and linear width of fringe?
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0answers
26 views

Boundary conditions for enthalpy waves inside a pipe

So I'm trying to solve a form of the wave equation for sound produced by a vortex distribution $\vec{\omega}$ convecting at velocity $\vec{v}$ . $$\left(\frac{1}{c_0^2} \frac{\partial^2}{\partial ...
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2answers
103 views

Linear vs. quadratic dispersion relation

In wave mechanics the dispersion relation between frequency $\omega$ and wave number $k$ is linear: $$\omega_n=c k_n$$ But in quantum mechanics, based on Schrödinger's equation, one can show that we ...
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5answers
287 views

What happens to waves when they hit smaller apertures than their wavelenghts?

I was wondering this for quite a long time now. Let's say you have a water wave (like ripples, not the ones you see during tsunamis) with wavelength 10 m. Imagine you put a boundary with an opening of ...
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1answer
27 views

Sound Wave interference Experiment

I was wondering, can we use two sound sources so as to create a destructive interference at the position of a recorder at home? If possible, what is the easiest way?
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0answers
23 views

Frequency dependance of sound wave reflection

Why are high frequencies reflected more than low frequencies off an 'acoustically hard' surface such as concrete? I basically understand that the amount of reflection is determined by the impedance ...
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1answer
29 views

Meaning of ideal membrane

I'm studying from a mathematical point of view the bidimensional vibrating membrane. How can I define an ideal membrane? What are the assumptions when I say 'ideal'? Thanks!
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2answers
114 views

Are there any ways to alter frequency of wave?

I want to know how can we change frequency of wave, both sound and light, and what is the nature of "changing frequency" Such as, any material could absorb and re-emit wave in another wavelength. Or ...
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0answers
15 views

Can radial mode standing waves exist in a column of gas?

In a solid bar such as aluminum one can excite transverse, longitudinal and torsional standing waves. In a column of gas bound within a tube, whether open-open, open-closed or closed-closed, physics ...
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0answers
13 views

Distribution of refractive index of water when applied pressure wave

I was wondering when applying pressure wave, ultrasonic sound waves, under water, how I would be able to measure the distribution of the refractive index.
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0answers
21 views

Sound vibrations for marine propulsion

I asked a similar question about bubbles making less friction on a mass moving through water, now I'm wondering of sound waves could do the same thing as supercavitation or possibly create it's own ...
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1answer
48 views

Thin-wedge Interference Problems (Classical Waves Problem)

I would like to solve the problem on the following image: My question is: Why is the answer to (a) a minimum? When the light wave hits the top surface of the top glass, a wave will be reflected ...
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2answers
64 views

about superposition of two sinusoidal waves

I am reading a material on introduction of interference and superposition. To go deeper, I want to know how the math works in superposition, from wiki ...
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0answers
27 views

Modeling the creation of transverse waves

Suppose I hang one end of a jump rope against a wall and start waving the other end. I'm interested in knowing the behavior of the jump rope as it starts generating waves. In other words, how can I ...
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1answer
20 views

Intensity of Sound Wave

Is the intensity of a sound wave same at all the points through which the wave travels? The formula for intensity is $ I = \frac{{p_0}^2 }{2 \rho v}$. But this does not make sense to me. Shouldn't the ...
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1answer
216 views

Does a wave experiencing a total internal reflection penetrate the medium in any way?

Let me explain my concern usingn this picture: At the point of total internal reflection does a fraction of the wave get into medium 2? I would imagine it should happen because of the uncertainty ...
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0answers
18 views

Standing waves on a compound string

I've been having some difficulties in understanding standing waves. The questions that I have are as follows: 1) Suppose I have a compound string, made up of two strings. What is the correct way to ...
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0answers
36 views

Destructive and Constructive Interference Sign Problems in Sound Speakers

The problem statement, all variables and given/known data Problem b). Looking at the attached document of my teacher, the visual representation of the answer does make sense. Relevant equations ...
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0answers
18 views

Appropriate order of the sources in the phase difference formula (Waves)

Please look at b). My teacher defines delta(x) to be x1-x2 and then says that phi naught of 1 =0. However, because she defined the difference to be "1"-"2", the phi naught difference should also be ...
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3answers
55 views

Double-Slit Experiment Separation Between Fringes

I was taught in class that the double slit diffraction pattern would always have bright fringes of same length. We derived the formula: $y=m(\lambda)(L)/d$, which also shows this equal distance. I ...
2
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1answer
48 views

Why is a particular wavelength favored by transmission through a thin film?

A sheet of glass is coated with a $500\text{ nm}$ thick layer of oil ($n=1.42$). For what visible wavelengths of light do the reflected waves interfere a) constructively? b) destructively? ...
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1answer
27 views

Propagation of sound waves and monopole

While it is understood that in order for the acoustic waves to reach far field the wavelength should be less than the characteristic length of the source, I am not able to physically understand how? ...
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0answers
29 views

Radar Vs. Sonar

What is the true difference between radar and sonar? My understanding is that radar uses a reflected EM wave, while sonar uses a compression (shock wave) of the material it's in. (It compresses water, ...
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1answer
82 views

Why can we leave off half of the general solution?

In these pdf notes, it says at the bottom of the first page and beginning of the second: [...] whose solution is: $$\Psi(\theta) = c_1 e^{i\omega\theta} + c_2 e^{-i\omega\theta}$$ Since we are ...
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2answers
36 views

Is there a specific branch of physics that studies waves?

Is there a branch of physics that studies waves and how they propagate through air, wires etc.?
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1answer
62 views

Spherical wave amplitude near to source

Let us assume, I generate spherical waves from a point source, of the form $f(t)=\sin(t)$. At $r$ distance, it will be $\sin(t)/r$. Let us take $r = 0.1$ for example. Then, at this distance, the ...
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0answers
21 views

What is the physical explanation for the phase relationship between acoustic pressure and particle velocity in plane and spherical waves?

I've been looking around for a decent physical explanation of the differences in the phase relationships between acoustic pressure and particle velocity in different types of waves. Mathematical ...
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0answers
12 views

What the phase constant difference required for sources located at the same location?

Here is what my teacher wrote on her notes: Let's say there are two speakers located at x=0m emitting sound waves of same $\omega$ and same A. PHASE CONSTANT DIFFERENCES If A < A'<2A: there is ...
2
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1answer
53 views

General equation of a wave

My book says that functions which represent a wave motions satisfy the differential equation : $$ \frac{\partial^2 y} {\partial^2t} = v^2 \frac{\partial^2 y} {\partial^2x} $$ where $v$ is the ...
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1answer
24 views

Modulus of rigidity inside the water

Transverse wave can't travel inside the water. It travels in solid and on the surface of water because they have modulus of rigidity. What is modulus of rigidity? and why there is no modulus of ...
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2answers
72 views

What is the mathematical equation for a sine wave? [closed]

(Guitar player and programmer here, don't know much about math. So go easy ;) ). I recently learned that an audio sine wave is called that way because it is of the shape of the graph of a sine ...
2
votes
1answer
68 views

Equation of motion for system of springs

I need to find the equations of motion for the following system. If $x_1$ is $m_1$'s extension and $x_2$ is $m_2$'s, then, I feel like for $m_1$ we just need to consider $x_1$ giving $$m_1 a_1 = ...
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0answers
16 views

Sound Source Power Formula Approximation

A sound source emits waves with a wavelength of 25 cm. 50 m away, the waves have an amplitude of 4 micrometers. It's 20 ° C outside and the density of air is 1.3 kg/m^3. What is the power of the ...