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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Trying to read phase shift constant from the graphs

I have an equation $y(x,y) = y_0 \sin (\omega t \pm kx \pm \phi)$ and there are two graphs. One is $y(x,t=0)$ in units $mm(mm)$ and the other is $y(t,x=0)$ in units $mm(s)$. Now I have to find all of ...
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1answer
25 views

Group Velocity of guassian packet equals time derivative of mean position?

If I look at a gaussian wave package, and then interpret (in the usual Quantum-Mechanics Way) its square value as the propability density, then I can calculate a mean value for the position: $$ x_{...
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1answer
22 views

Curious about headphones [on hold]

So I'm trying to learn more about headphones. I have a small piston that is in a small sealed volume (the earcup, say it is $25\, cc$). And there is a front volume between the piston and the ear (...
3
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1answer
121 views

Is dispersion a property of medium or wave

I got a problem in learning Lewin's 'Vibration and Waves'. He first solve the eigenvalue of 5 beats connecting together and with fixed boundary condition. Then the velocity for different modes are ...
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0answers
31 views

Relative velocity between phase velocity wave and a group velocity wave

It is said that material particles have a dual nature. A particle is associated with a wave which travels with phase velocity and the particle travels with group velocity. These are related by $$v_\...
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1answer
25 views

Standing waves due to two counter-propagating travelling waves of different amplitude

Suppose I have two counter-propagating travelling waves of the same frequency but of different amplitude, like the transverse waves produced in a string by partial reflection off an endpoint. I read ...
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0answers
25 views

Beats: frequency of resulting wave vs. beat frequency

The beats frequency heard from the interference of two sound waves with frequencies $f_1$ and $f_2$ is $$\nu=|f_1-f_2|$$ Nevertheless the frequency of the resulting wave is not $\nu$ but the mean ...
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3answers
107 views

Significance of wave number?

Till now all I know about the wave number is its formula i.e. ${\frac{2\pi}{\lambda}}$. I always wanted to know what it really means. So can anyone please, explain me its physical significance?
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25 views

Sound waves - physics [on hold]

A closed organ pipe of length L is in resonance with tuning fork. If a hole is made at a distance L/4 from the closed end will there be resonance again? If so when?
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0answers
25 views

Waves: Phase Difference [on hold]

I know this is a somewhat elementary question, but I have always had some trouble mastering this material (this kind of question in general): Suppose two microphones are the same distance from a ...
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0answers
23 views

Conditions to find standing waves harmonics

I came up with a doubt on standing waves conditions. The type of question I find difficult to answer is of the following type. Consider a rope. I do not know if the rope is fixed at both end or at ...
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3answers
52 views

Can sound travel in the form of transverse waves?

We all know that sound is a longitudinal wave but in some books, I have found that sound travels in the form of both longitudinal and transverse waves while passing through rocks. Can anybody explain ...
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1answer
32 views

Situations in which there is path difference interference or formation of standing waves [on hold]

I came up with a doubt about standing waves and path difference in general. Consider these two different cases as examples. If I have a rope fixed at one end and I make the free end oscillating, I ...
4
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3answers
503 views

Is there any effect on mechanical waves by electromagnetic waves (and vise versa)?

Do electromagnetic waves like light and gravitational waves (due to moon for instance) affect on mechanical waves like sound? Can sound change the path of light?
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0answers
24 views

Wave equation for odd spacetimes and source terms

It seems to be quite common practice, when solving the wave equation in spacetimes with odd topologies or horizons, to decompose the solution into a sum of the various origins (or destinations) of the ...
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1answer
37 views

Vibrations of a string [closed]

A string with length $L$ is stretched between two fixed points. The string can't vibrate with which wavelength? Four options are given, namely $L$, $L/2$ , $2L$ and $4L$. I know that the ...
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3answers
135 views

Why do we hear better during the night? [duplicate]

At night, we hear weak and far sounds approximately clear, while during the day we cannot. My high school physics teacher was saying that “this is because of interference of sound waves. During the ...
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1answer
2k views

Why do you only hear the bass when someone nearby is wearing earphones?

When someone nearby is listening to music through earphones or headphones, usually you can only hear the bass (unless it's really loud where you can hear the singer's voice and the other instruments ...
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0answers
33 views

Did de Broglie deduce E=pc? [closed]

IIUC, $E=mc^2$ follows from $E=pc$ if $p=mc$ and $pc=hf$ is the same equation as the deBroglie wavelenth. Is it safe to say that $E=pc$ is an equation by de Broglie or is that equation some other ...
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1answer
57 views

Conservation of energy in interference of light

In interference of light, I know that energy is conserved globally but how the energy disappeared at minima appears at maxima? Is there any path by which energy flowed or is it just energy couldn't ...
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0answers
25 views

3D wave equation of a 3D object [closed]

For an example I have to derive wave equation of a sphere, x^2 +y^2 + z^2 = r^2 and its solution (wave function). Boundary condition can be anything. I like to know about eigenvalue and its use at ...
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1answer
16 views

What happens when sound source is radiating through a hole in a cavity?

What happens to the external sound field , when loudspeaker attached to one wall is radiating inside a box and other wall has a aperture size of a diaphragm? Do we experience Helmholtz effect?
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31 views

Plane wave propagation [closed]

Can anyone help me please understand how this is done? and whats epsilon ? many thanks
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3answers
30 views

Water in glass tubes producing different pitches when tapped. Why exactly is this?

So I've been making a DIY instrument for my physics project at school. I decided to try this experiment where I put different volumes of water into a glass cup, and I tap it with a spoon to create ...
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2answers
50 views

What is the difference between real value and abs value? [closed]

I am confused here, though I have been reading about it for years. What is the difference between a real value and an absolute value? For example, when do we take the absolute value of pressure or the ...
3
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2answers
126 views

Minimum frequency of an electromagnetic wave

Is it possible to create an electromagnetic wave of near zero frequency? An electromagnetic wave carries energy. If we can make the frequency of an EM wave vanishingly small and make it practicality ...
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2answers
46 views

Why monochromatic waves exist even theoretically

I was reading this question. Where the author made a statement that If I take a wave with period T, it is also true that it has a period 2T, 3T and so on. That is, it has frequencies of 2π/T, but ...
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2answers
200 views

why does the frequency of a wave remain constant?

They say the frequency of a wave is its fundamental character, thus remain constant throughout its propagation regardless the medium through which it travels. Could anyone explain why frequency of ...
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0answers
60 views

Why are FM radio waves less susuceptible to interference than AM? [duplicate]

When studying modulation of radio waves (or of most electromagnetic waves for that matter) I came across that question. Why are FM waves less susceptible to interference than AM waves? I know that in ...
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0answers
37 views

Is there any solution manual to A.P. French's 'Vibrations and Waves'?

I'm trying to work through A.P. French's Vibrations and Waves. Unfortunately, I can't check the details of my solutions since the solutions aren't given with the textbook. Does someone know where I ...
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0answers
16 views

light interference [on hold]

Recently while driving, i noticed that when it is dark, the light emitted from an incoming car with its headlights at full strength (bright) and with mine also at the same state, my windscreen sort of ...
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1answer
22 views

Reason for absorbance

First quoting the example which raised my curiosity"when light passes through polaroid it absorbs certain direction light rays" My question is how this phenomenon of absorbance occurs is this some ...
0
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2answers
58 views

Why do we hear a different timbre when someone speaks with helium (or other gases) in their lungs?

Let me make one thing clear: I am fully aware that the change in timbre comes from the change in acoustic wave speed when going through a different medium (just like light). However, would I not ...
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1answer
45 views

Fresnel zone with different antenna heights

I've looked at the formula to calculate the first Fresnel Zone: $$r=17.31 * \sqrt{\frac{d_1*d_2}{f*d}}$$ whereby $d_1$ and $d_2$ are distances from the obstacle to the link end points in meters, $r$ ...
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1answer
21 views

Will phase change occur in the formation of standing waves?

I have learned that standing waves are formed by two waves overlapping with each other where the two waves are the same in wavelength, frequency, and amplitude. I have a doubt in how the phase of ...
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1answer
47 views

Explanation of sounds waves and speed.

When a rocket is traveling toward a mountain at 100 m/s, the sound waves from this rocket's engine approach the mountain at speed V. If the rocket doubles its speed to 200 m/s, the sound waves from ...
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1answer
50 views

Direction of momentum given by the de Broglie relation

The momentum of an electron can be computed by the well-known classical mechanics equation: $p=mv$ where $m$ is the mass of an electron, and $v$ is its velocity. In this case, since $v$ is a vector,...
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2answers
47 views

Can localized fluid perturbations be accelerated by pressure gradients?

I would like to know if there are any examples in fluid dynamics (or continuum dynamics) of small perturbations (or waves, solitons, or other "localized" solutions of the fluid) being accelerated in ...
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0answers
37 views

what is the plane of the matter waves?

We all know that in an electromagnetic waves there is one wave whose plane is perpendicular to the other. so you see that there is a plane and every book which i have read shows the same. now i come ...
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1answer
105 views

Which arrangement of pipe and sources can create a standing wave?

A loudspeaker emitting sound of frequency f is placed at the open end of a pipe of length l which is closed at the other end. A standing wave is set up in the pipe. A series of pipes are then set up ...
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2answers
41 views

Independence of Period and Amplitude in Simple Harmonic Motion

In Simple Harmonic Motion, the period $T$ of an oscillation, is said to be independent of the amplitude $A$ of an oscillation, but why is that so? Attempting to derive from the equations of Simple ...
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3answers
50 views

Why do we add intensities for coherent sound sources?

When there are N coherent sound sources playing the same note at equal loudness, their sound waves add up to make a sine wave of the same frequency but most likely different amplitude (can be anything ...
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0answers
23 views

Seeing vs hearing a wave [duplicate]

Two questions came to my mind after reading the 4th para of the 1st answer of this question... Although we can't hear a 35Hz wave, can we see the object vibrating? Is there a range of ...
0
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6answers
107 views

Standing waves: why do 2 standing waves don't cancel each other?

I have learned that when two waves are combined, the peaks and troughs could be in the same direction (so that means the amplitude is increased) or the peaks and troughs could be in the opposite ...
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2answers
41 views

How are sound waves of different speeds heard differently?

Lets say that there are two waves. They are both identical in every way except that one is traveling through a gas and another through a liquid. As we know they are traveling at different speeds and ...
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2answers
87 views

Are light waves sinusoidal functions?

I was researching sinusoidal functions when I realized that the wave produced by a wave function looks exactly the same as a light wave. Is a light wave a sinusoidal wave, and can a light wave be ...
0
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2answers
60 views

why cannot longitudinal waves travel through space (vacuum)

'The reason sound can't travel through a vacuum is that sound needs a medium (solid, liquid or gas with real vibrating molecules) and not because it is a longitudinal wave' How does this make sense as ...
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1answer
94 views

What is y(x,t) = Acos(kx - wt)? [closed]

Im very new to wave mechanics and I've come across the following wave equation. I know this is asking too much,but I wanted to know what is the significance of this equation? what does it tell us / ...
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0answers
57 views

Meaning of a Dirac delta speed in 1d shallow-water equations

A 1d thin layer of a fluid of constant density in hydrostatic balance can be modeled by shallow-water equations: $$\begin{align*}\partial_tu+\partial_x\left(v+\frac{u^2}{2}\right)&=0,\\ \...
2
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3answers
83 views

Why do we say gravitational waves are analogous to sound?

In every popsci discussion of gravitational waves, the waves are said to be like "sound", and that gravitational waves allow us to "hear" the universe. Despite this, I have no idea how gravitational ...