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.

learn more… | top users | synonyms (1)

3
votes
2answers
87 views

Patterns in laminar flow of tap water

This is a simple experiment that anyone can do at home. Open your tap so that the water maintains a laminar flow, and the cross section of flow is considerably thin. Place your finger 3-4 cm below the ...
0
votes
2answers
98 views

What is the significance of angular frequency $\omega$ with regards to wave functions?

What is the physical significance of $\omega$ in a function like $$ f(x) = Asin(kx + \omega t) $$ The only place that I am familiar with angular frequency is when dealing with circular motion, but ...
0
votes
1answer
53 views

Fourier series for a wave on an infinite string?

From "Vibrations and Waves" by A.P. French I know that any wave on a string length $L$ can be represented by: $$y(x,t)=\Sigma^\infty_0 A_n \sin(\frac{n\pi x}{L})\cos(\omega_nt-\delta_n)$$ But can we ...
0
votes
2answers
155 views

Are matter waves (de Broglie) classified as transverse or longitudinal? [duplicate]

We know that waves are of two types: transverse and longitudinal, and we have studied about de Broglie waves as well, so which one of them is it? Or we have other means to classify them?
1
vote
1answer
60 views

What is slinky-approximation?

I was reading the derivation of wave-equation from Berkeley Physics - Waves by Frank S. Crawford Jr. Let $\Delta z$ be a small segment of a continuous string . At equilibrium, tension is $T_0$ at ...
4
votes
3answers
109 views

What makes waves propagate?

Why do electromagnetic waves propagate? I have searched a lot about EM waves, but I am still unable to understand what is driving them. Could you explain?
1
vote
2answers
81 views

Singing for physicists: How to resonate by body cavities with my voice?

My body has various cavities, such as my throat, mouth, chest, and nose. This cavities have resonant frequencies. I also have a voice box, which creates sound. How do I create sounds at the resonant ...
2
votes
2answers
189 views

How do waves have momentum?

A question on a practice test I'm taking is as follows: By shaking one end of a stretched string, a single pulse is generated. The traveling pulse carries: A. mass B. energy C. momentum D. ...
1
vote
1answer
41 views

Question regarding charge and acceleration

From a stationary charge electrostatic fields arise. From a moving charge, magnetostatic fields arise. From an accelerating charge, EM waves arise. So i wonder -- what about a non-constantly ...
0
votes
0answers
50 views

Direct interaction theory

I got to know about a kind of theory or formulation of EM which doesn't have the idea of fields in it. In that theory I guess field isn't that which mediates the force between two charged particles. ...
1
vote
1answer
52 views

Sound waves and chromism?

I am definitely not a physicist, but I have a question related to Physics so I thought I'd give it a try. Please excuse my ignorance. :) I am somewhat familiar with the changes in color caused by ...
1
vote
0answers
17 views

Phase change by reflection [duplicate]

Let's consider a light ray falling on a cuboid made of glass at the angle $\alpha$. Then there will be a reflected ray $A$. The ray will also refract. Let the refracted ray be $B$. Ray $B$ will be ...
1
vote
1answer
32 views

In a noiseless environment, how accurate do today's transmitters send EM waves?

Suppose that there is no external noise in the environment. How accurate are today's TEM wave transmitters in such a case? So if we want to send $200\cos(1000\pi t)$, can transmitters send exactly ...
1
vote
0answers
43 views

The interaction between waves and particles according to their wavelength [duplicate]

Why do EM waves with a large wavelength like those in the red range (and radio waves) interact with particles less than those in the blue range? That is the reason why the sky is blue, is that right? ...
1
vote
1answer
47 views

Is it possible to “pull” sound waves using only an object?

Say, for instance, I am outside standing 20 feet away from a speaker. Is there an object I can put on my body that would allow me to feel the bass of the music more, without picking up the vibrations ...
0
votes
1answer
69 views

Reflection of Sound wave (Pressure Wave)

I want to study about the phenomenon of reflection of pressure waves as in an open ended organ pipe. Please suggest a suitable resource? I know about the harmonics in a stretched string and I can use ...
1
vote
0answers
28 views

How can we detect the property of matter by using mechanical waves or IR or any other way

First of all, I am in high school[to tell that I don't know much physics]. And the second thing is that, I am not sure whether this question is specifically related to physics. What I want to ...
7
votes
2answers
885 views

What should be the intuitive explanation of wave equation?

$$\dfrac {\partial^2 y}{{\partial x}^2} = \dfrac{1}{v^2} \dfrac{\partial^2 y}{{\partial t}^2}$$ is the wave equation in one dimension. But what should be the intuition behind it? That is, what meaning ...
0
votes
0answers
28 views

How fast does the force of pulling a straight rope propagate along the rope? [duplicate]

Is it instantaneous or does it somehow propagate like a wave along the particles of the rope ?
2
votes
1answer
59 views

How does energy get transfered from destructive interference point to constructive one?

If there are two pressure waves (like sound waves) that travel in opposite directions and have the same amplitude then destructive interference occurs: one wave will compress the air particle (here ...
3
votes
3answers
131 views

Why is there a negative sign in front of the optical wave?

In undergrad I lost (a lot) of marks in my optics class for writing: $$A(t) = \exp(i(\omega t + \phi))$$ Instead of: $$A(t) = \exp(i(-\omega t + \phi))$$ In a derivation where I must have needed ...
4
votes
1answer
47 views

Interference and windows

The other day i was learning about interference patterns with the effect of a bubble making a rainbow on the surface. I learned that the reflections from both sides of the soap can interfere ...
0
votes
0answers
50 views

What have we built? A resonant loop antenna? Rhombic?

Some background, my partner and I have built an antenna we are supposed to characterize for an assignment, and compare it to physical predictions. However, we don't know what type of antenna we have ...
0
votes
0answers
23 views

Intrinsic Impedance Clarification

Can somebody explain to me what it means to have a complex intrinsic impedance? I realize that it happens in lossy media and know the formula but am looking for comprehensive insight
16
votes
7answers
852 views

Physics of how the cochlea isolates frequencies along its length?

Can anyone explain the separation of frequencies along the basilar membrane of the cochlea please? (equations would be nice) I understand it being related to the resistance caused by fluid in the ...
0
votes
0answers
16 views

Can TEM waves have constant offsets - that is, mean of non-zero in context of Poynting's theorem?

Suppose the electromagnetic wave and the corresponding magnetic field wave are TEM waves. Can such waves have overall mean of non-zero? (so DC offset) If they do, what do they mean in context of ...
2
votes
1answer
53 views

Maximum Penetration Depth for Ultrasound

How do you define the maximum penetration depth of an ultrasound? I'm assuming it means the depth at which the wave has attenuated to a certain small percentage of the original intensity of the ...
0
votes
1answer
347 views

Relationship between temperature and wavelength?

I am investigating the relationship between wavelength and temperature. As seen the figure below of Planks law What is the relationship between the lambda(max) and Temperature? or in simpler ...
1
vote
0answers
117 views

Beat frequency for 3 waves

Consider 3 waves of frequency 101, 103, 106 hz, and of same intensity. What should be the beat frequency. Now I can calc it for 2 waves, and i know how to write the combined equation of the two. But ...
2
votes
0answers
37 views

What criterion did Abbe use?

For a microscope (correct me if I am wrong) the Rayleigh Criterion gives us: $$ R=\frac{1.22 \lambda}{NA_{condenser}+NA_{objective}}$$ But with the Abbe diffraction limit: $$ ...
0
votes
2answers
112 views

How does light oscillate?

Why do we say that electromagnetic wave is oscillating? Or does light propagate really in a wavy form like this image? What is making the photons oscillate and how is it oscillating is it ...
0
votes
1answer
32 views

Difference between a light wave in space and a wave in a pond

Apart from their nature and the medium utilized, what are the differences between an EM wave and a wave we see in a pond? When we throw a stone into a pond, can we imagine we are observing light ...
0
votes
1answer
93 views

Understanding wave packets, in particular matter waves, dispersion and point particles

Here is what I have gathered so far: Particles like an electron (i.e. with rest mass) can be represented as matter waves (deBroglie). The matter wave of a particle can be modelled a wave packet. A ...
2
votes
1answer
300 views

Wave on a guitar string, differential equation

The mechanical energy of an element of the string is : $$dE(x,t) = \frac{1}{2}\left[T_0\left(\frac{\partial y}{\partial x}\right)^2 + \mu\left(\frac{\partial y}{\partial t}\right)^2\right]dx$$ Where ...
0
votes
1answer
96 views

Do Sidebands mean the frequency of an AM radio wave is not constant?

I'm studying for A-level now..... I have read some other posts explaining how the sidebands generated after the carrier wave is modulated. So, if there is sideband frequency, the frequency isn't ...
1
vote
0answers
79 views

A level 9702/11/o/n/14 question 26 (about interference of sound wave) [closed]

The speakers are identical and they are connected it's series with power, so I thought there would be complete destructive interference. Therefore, at some point the amplitude would be zero and also ...
0
votes
0answers
102 views

Wave equations for reflected waves in standing wave calculations, when the end is fixed and when it is free?

Consider a sinusoidal wave moving in the +x direction $$y_{1}(x,t)=A\sin\left [ \frac{2\pi }{T} \left ( t-\frac{x}{v} \right )\right ]$$ (A) At a fixed end, the amplitude of the resultant wave ...
0
votes
1answer
69 views

How can I decrease the volume of a sound wave?

I have a sound wave in a computer, represented as a series of values (samples). Each sample is in the range roughly between -30000 and 30000. Say I want to decrease the loudness of the entire wave by ...
0
votes
2answers
38 views

How can I add two sound waves without reaching distortion - always keep them under a certain value?

I'm working on a program that adds sound waves on top of each other. I read that the best way to do that (correct me if I'm wrong) is to simply add them together. However, this way I easily reach ...
0
votes
1answer
48 views

How can I add a sound wave on top of an existing one, without harming the original's loudness?

I'm working on a program that has to do with adding sound waves on top of sound waves. Currently what I'm doing is simply an average of the two waves. So if I have wave ...
0
votes
1answer
82 views

How do particles in a wave make the next particles move?

i only know few things about waves,but this question just popped up in my mind. I already know that the particles transfer energy to each other,but i do not know HOW they do it! The truth is that i ...
2
votes
1answer
34 views

Solitons and its infinite extension

A soliton, for example the KdV equation solution, has the profile proportional to a hyperbolic secant squared ${\text{sech}}^{2}(x-ct)$. And since it is hyperbolic it has an exponential dependence, so ...
0
votes
0answers
21 views

Time for water wave to reflect

In class we discussed an experiment for measuring the speed of waves in water. The basic procedure went something like this: Make a wave at the near end of the tank and wait for it to travel to the ...
1
vote
2answers
147 views

relationship of number of standing waves with Temperature?

If we have let us say fixed air column of length 'L', in a open-closed column problem, lamba is equal to 4*L/(2n-1). n = number of nodes / anti nodes in air column How does 'n' changes with ...
0
votes
1answer
127 views

The wave equation, methods of solving and superposition of waves?

I have some questions concerning the wave equation: $${\partial^2 y \over \partial x^2} = {1\over c^2}{\partial^2 y \over \partial t^2}$$ Firstly, does the method of separation of variables give ...
0
votes
0answers
15 views

Solution for elastic wave on plane of ideal contact between two half spaces of elastic, homogeneous, isotropic, linear solids

Please give the solution for elastic wave of arbitrary polarization incident at arbitrary angle on plane of ideal contact (meaning no slip, homothermal, nondissipative, and no transfer of material ...
2
votes
1answer
54 views

Non resonant modes in cavity

I have a simple question. Suppose we have a laser with a cavity such that the frequency of the light that the laser emits does not match with any longitudinal modes allowed by the cavity. In ...
2
votes
2answers
125 views

Are standing waves in water exact sine waves?

In many physics demonstrations waves in water are used to illustrate principles of standing waves and wave propagation. After such demonstrations, classes tend to move on to basic problems ...
0
votes
0answers
15 views

Zero stress boundary conditions for the acoustic wave function

When is it appropriate to use zero normal stress boundary conditions when solving the acoustic wave equation. That is when the pressure is equal to zero.
0
votes
1answer
38 views

Can surface waves exist near a fixed surface

(I'll phrase this question in terms of waves in an elastic medium, but this is a more general question.) Surface waves are waves near the surface of a medium whose amplitude decreases as you go away ...