Waves are disturbances that propagate through 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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Energy conservation in interference?

Does interference of light follows first law of thermodynamics? If yes then where does light vanishes in minimum interference pattern?
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99 views

How does one measure the phase of a wave?

Given an electromagnetic wave of unknown characteristics, is it possible to measure its phase? Or does it always have to be inferred from interference with another wave (e.g. beating etc.)?
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147 views

Why do not the ripples on a pond form a 3 dimensional wave?

I can see that that the expansion of the the circles happens in a two dimensional plane. Therefore, we say that a two dimensional wave is formed. But, why cannot we count the vertical disturbance so ...
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Pouring oil on choppy water to calm it , does it work and if so how?

Near where I live, local fishermen often bring cans of castor oil with them, to calm the water around their boats, if they feel bad weather is due. They claim this method of sea calming works, (...
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48 views

Waves ionsphere?

Explain why the ionosphere can be treated as a plane mirror when transmitting short-wave radio, even though it is a curved surface. Is it because the area involved is small?
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222 views

Why is the wave equation so pervasive?

The homogenous wave equation can be expressed in covariant form as $$ \Box^2 \varphi = 0 $$ where $\Box^2$ is the D'Alembert operator and $\varphi$ is some physical field. The acoustic wave ...
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116 views

Determine beat frequency

I am currently trying to create a plot of the beat from superimposing two sine waves. I know the formula is given by $$\sin(\omega_1 t)+\sin(\omega_2 t)=2\cos\left(\frac{\omega_1-\omega_2}{2}t\right)...
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158 views

How do we know that the CMBR is the oldest light?

How do we know that the CMBR is the oldest light which we can see? Is it based just on the facts 1.that waves redshift with expanding space, and 2.predictions of the big bang theory; Or is there a way ...
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152 views

Power of a wave in a string

My text of physics, Gettys', shows how the energy, both kinetic and potential, of a small element $\Delta x$ of a string, through which a wave (whose wave function is $y:\mathbb{R}^2\to\mathbb{R}$, $(...
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115 views

Conventionally, how many amplitudes does a (harmonic) oscillator pass through in one full cycle? [closed]

I don't know the typical scientific convention. My book says there are 4 amplitude. But no matter where I start the oscillator , the answer is at most 3.
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504 views

A heavy rope is attached to one end of a lightweight rope [closed]

If one end of a heavy rope is attached to one end of a lightweight rope, a wave can move from the heavy rope into the lighter one. (a) What happens to the speed of the wave? (b) What ...
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96 views

How large or small can frequency in the EM spectrum get?

The largest frequency range is gamma rays, but does the EM spectrum 'stop' somewhere? Like is there a limit to how large a frequency can get? Or how small frequency can get? Is it one of those things ...
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249 views

What really is the significance of the resonant frequency in terms of “ease of vibration”?

I was studying the concept of resonant frequency and I've read quite a few articles and notes on it. What I have understood from what I have read is that the resonance frequency of an object is its ...
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42 views

What is the Optimal Separation Length for the Tines of a Tuning Fork?

I'm building tuning forks (for fun... why not?), and among one of the design decisions is how far apart should I place the tines (the two long prongs) from each other. I'm not entirely certain whether ...
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1answer
364 views

Physical meaning of wavelength of an EM wave

What is the physical meaning of the wavelength of light? This question has been asked before but I cannot find a satisfactory answer. Some respondents have said that the question is vague, I don't ...
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1answer
184 views

Differentiating between standing waves (stationary waves) and progressive waves [closed]

The question is ''Differentiate between standing waves (stationary waves) and progressive waves?" I do not understand what exactly they would like to hear. Should we talk about the frequency, ...
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2answers
344 views

Why does a continuous water stream form ripples when colliding with a surface? [duplicate]

I was in the shower one day washing my hair, and noticed that the water falling off my hair formed perfect streams that ceased to break into droplets for quiet some distance (probably about 5-6 cm). ...
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4answers
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How to derive the formula for phase difference $\Delta \Phi = \frac{2\pi}{\lambda}\Delta x$?

How can I derive the formula $$\Delta \Phi = \frac{2\pi}{\lambda}\Delta x$$ for calculating the phase difference? On a relative note, why does the particle velocity have an upwards direction when ...
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0answers
98 views

Amplitude of wave with distance

How is the amplitude related to distance with waves on a plane? I am creating a mathematical model for water waves in a ripple tank, first assuming that there are no other factors that may affect the ...
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76 views

Wave propagation in micro strip waveguide

I am trying to understand wave propagation in micro-strip waveguide, the way i came to understand rectangular waveguide is this way (in brief): EM waves can be understood as reflecting from the ...
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177 views

What is the relationship between the velocity of an object and its Sound Intensity Level in an inelastic collision?

Assuming the mass, acceleration, and height of the dropped object are constant and the area of the measured sound wave is constant, would the relation be linear, exponential, logarithmic, square root ...
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23 views

How is the frequency unchanged in elastic wave scattering with a crystal?

it makes sense that with an inelastic scattering process, a wave approaches a crystal, and then some energy is imparted to the phonons, so that the outgoing wave has a different frequency from the ...
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203 views

Why do I hear voices when I touch my turntable needle?

So I was trying to figure out the reason why my old (and probably sufficiently damaged) needle on my phonograph (turntable) was not working like it was a little while ago. With my headphones on, I ...
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108 views

thin film interference of light

In a thin film interference (reflective system) I know that condition for maxima is $$2\mu t\cos(r)=(2n\pm 1)\frac{\lambda}{2}$$ and for minima is $$2\mu t\cos(r)=n\lambda$$ and for transitive system ...
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201 views

How does infrared radiation increase temperature?

Temperature is proportional to the average kinetic energy of particles in a medium. When impinged by infrared radiation, what happens on the microscopic level that translates that EM wave into the ...
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42 views

Dispersion relation in wave guides

I am reading Griffiths section 9.5. Assume that wave guides are surrounded by perfect conductors, and geometry is $z$-independent, as in the text. I understand he proved that in a hollow wave guide, ...
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185 views

I made a tin can phone using a plastic slinky and paper cups. Why didn't it work?

After watching some videos on Khan academy in regards to the information theory, I spent a few minutes creating a primitive "tin can phone." The materials of my phone are a plastic slinky and two ...
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278 views

Constructive and destructive interference

I read this information off a website: "The most important requirement for interference is to have at least two waves. One wave alone behaves just as we have been discussing. We shall see that ...
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372 views

How do gravitational waves work without internal tension?

One implication of general relativity is the concept of gravitational waves or gravitational radiation, ripples in spacetime thought to travel at speeds close to the speed of light. As far as I have ...
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1answer
63 views

What are the proper unit types for the calculation of the frequency of a tuning fork? [closed]

Wikipedia Article on the subject The formula states that the calculation of the frequency with cylindrical tines should be $$1.875^2/(2\pi L^2)\times(Er^2 /(4P))^{1/2}$$ where the variables are ...
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2answers
175 views

Why is Heisenberg uncertainty principle not valid in waves in string?

We know from high school physics that when the incident wave is traveling from a low density region (high wave speed) region towards a high density (low wave speed) region on a string, the width of ...
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127 views

Is this diagram, concerning Young's double slits, inaccurate?

"This diagram" : My question is whether those lines (interference) have to originate from a single point. The diagram used to demonstrate what $m$ (path difference) means, has two lines originating ...
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2answers
63 views

How to understand that the electromagnetic wave propagates?

Don't the electric field and magnetic field have infinite range? When a charged particle moves, the electric field vectors at two different locations A and B should start to change at exactly the same ...
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57 views

Current Electricity

If $$ \frac{dQ}{dt} = I $$ and if an accelerated current produces E.M. waves (radiation), does that mean $d^2Q/dt^2$ (second derivative of a charge w.r.t. time) will give me the magnitude of the wave ...
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632 views

Why does sound wave suffer more diffraction than light waves generally?

Why do sound waves suffer more diffraction than light waves generally ? I would like more of a logical explanation rather than mathematical .
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179 views

Velocity profile of a viscously damped wave

For a test case, I want to determine the velocity profile of a viscously damped standing wave. By linearizing the density ($\rho=\rho_0+\rho'$) and velocity ($ux=ux'$), the continuity and Navier-...
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29 views

Waves interfere in angle equation

If we had two waves perpendicular to each other, with equations: $x=α \sin(ωt)$ (1) $y=β \sin(ωt+π/2) ==> y=β \cos(ωt)$(2) $\sin(ωt)^2+\cos(ωt)^2=x^2/α^2+y^2/β^2=1$ $x^2/α^2+y^2/β^2=1$ is an ...
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133 views

Why is a sine wave considered the fundamental building block of any signal? Why not some other function? [closed]

It is mathematically possible to express a given signal as a sum of functions other than sines and cosines. With that in mind, why does signal processing always revolve around breaking down the signal ...
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99 views

baryon acoustic oscillation

I have one question about baryon acoustic oscillation. I understand why we should have the baryon-photon fluid sound wave before recombination: Suppose we have a spherical overdense region. This ...
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190 views

How are standing waves a result of constructive and destructive interferences?

For constructive I can understand. But destructive I can't. I can not picture the shape of two pulses or waves maybe that form the resulting standing wave. The places where waves are canceled just ...
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138 views

Is sonic boom louder than the sounds that a object traveling at the speed of sound makes, if so why?

Here are the wave-front models for both: I am in an introductory physics course. Just learned about this. I am not entirely sure if sonic boom is louder. But from what I saw, it's loudness is ...
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1answer
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Reflection of an Electron

When a mechanical wave goes from one material to an other, some fraction of it returns back. Same thing with light (massless), but what happens with an electron? When the "wave function" changes ...
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3answers
351 views

Question about intensity of EM waves

For electromagnetic wave if it's reflected from a perfect conductor standing wave can be form. I wonder why Poynting vector can be used to describe the intensity of standing EM wave. (see p.19 of http:...
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192 views

Numerical Solution of the Propagation-Dispersion equation

I have asked this question on Computational Science and also on Mathoverflow, but no satisfactory answers so far. I thought maybe the physics community could shed some insight on the issue. I am ...
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28 views

concerning the effects of temperature and density on the speed of sound [duplicate]

here is my relatively broad question: how does the temperature and density of a medium effect the speed at which sound travels through it? Now I shall elaborate: it is my understanding that there ...
2
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4answers
301 views

What do light wave oscillations look like? [duplicate]

High school physics student here, so please bear with me for a moment. I know that light waves oscillate, but I don't know how. In textbooks and diagrams they're portrayed as wavy lines traveling ...
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70 views

Two supersonic planes. Do they hear each others sonic boom?

Plane A is traveling at Mach 2 and is over taken by plane B traveling at Mach 3. Does plane A hear the sonic boom from plan B? If so when? Does plane B hear the sonic boom from the slower Plane A? ...
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166 views

Can a standing wave form on a string with both end open

I am fascinated with an idea of an standing wave forming on a string with both end open. If we assume two identical waves coming in of an infinitely long string then for a short period of time, they ...
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Is an infinite Doppler effect plausible?

When I was young (which I still am) I was amazed by the sound jet fighters make when they break the sound barrier - a sound similar to an explosion which caused my school to shake. Later I learned on ...
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69 views

Interference of Beams with Different Polarizations

I have read in many places that orthogonally polarized light beams do not interfere. However, I also know that orthogonal vectors, such as force, do affect each other and give a resulting force. So, ...