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)

1
vote
1answer
30 views

Picking a guitar string of fixed length to get any nth harmonic, is it possible?

In physics textbook, we can calculate the nth harmonic of a vibrating string of a fixed length. How can we do this in a real guitar? For example, if I just pick a single open string, how can I get ...
2
votes
1answer
49 views

Solving wave equations with heuristic-like, analytic methods

Take a Klein-Gordon (KG) equation for a model exercise: \begin{equation}\frac{\partial^2 u}{\partial t^2}=c^2\frac{\partial^2 u}{\partial x^2 } - \Omega^2 u,\end{equation} with boundary and initial ...
1
vote
0answers
18 views

Could Bluetooth radio waves be used to pick up UV light [on hold]

i am a bit of a Physic novice. But i was wondering if someone could answer this and if they might be able to make a possible sugguest. i was wondering if it possible for a bluetooth to be able to ...
1
vote
0answers
15 views

About EarthQuake?

As you know in Nepal many aftershocks are coming and earthquake is related to physics as earthquake is also a longitudinal waves . I have some series of question as well as my thoughts about it? ...
0
votes
0answers
20 views

Would any interference maxima be missing in the double slit experiment? [on hold]

An aperture of 0.9mm of double slit forms a diffraction pattern on a screen placed 6.0 meters away when illuminated with light of wavelength 600 nm; the distance between two slits are not specified. ...
1
vote
0answers
17 views

Contradiction (?): DNA ion mobility vs diffusion constant

There is a certain confusion about DNA ion mobility and diffusion constant in the literature. Consider double-stranded DNA ions in pure water. DNA ions are negatively charged due to phosphoric acid ...
0
votes
1answer
16 views

Derivation of impedance matching formula

When matching impedances with a quarter wavelength coupler, how do I derive that its impedance has to be $$ Z_2=\sqrt{Z_1 Z_3} $$ where $Z_1,Z_3$ are the impedances of the adjacent materials?
0
votes
1answer
70 views
+50

Finding the frequency of vibration of part of a system

The setup: 4 spheres of diameter $d$ are suspended on a horizontal plane (magically). They are arranged in a square with length $l$ (the vertices are correspondent to the sphere's centers). The ...
4
votes
3answers
96 views

Diffraction of matter waves

By considering the De Broglie wavelength of particles, we discover that matter can diffract if passed through openings with itself. This poses a variety of questions, namely Can matter waves ...
0
votes
0answers
31 views

What discrete form of the wave equation do you need to use to make a wave simulation?

I'm working my way through these blog posts about the wave equation. All has made sense up until now. The wave equation is $$ \frac{\partial^2h}{\partial t^2} = c^2 \frac{\partial^2h}{\partial x^2} ...
1
vote
2answers
42 views

Can KE and PE of a small element of a transverse progressive wave be maximum simultaneously?

Maybe a string can be taken as an example to produce the transverse progressive wave.
0
votes
1answer
53 views

How far can you propagate something, anything, before it becomes 'background noise'?

An electric field, light, a movement of molecules; anything at all. What is the maximum distance they can go before they are 'noise' to an ideal measurement instrument? So if the distance is ...
0
votes
1answer
14 views

Amplitude Modulation in dispersive mediums

I'm reading the book "Physics of Waves" by Georgi. In section 10.2 he says that to send a signal through one-dimensional dispersive mediums where the dispersion relation is not $\omega(k)=vk$ ($v$ the ...
0
votes
2answers
32 views

Does every object, every particle and every thing have it's own resonant frequency?

The principles of resonance are such that the greatest amplitude of a vibrational or electrical wave peak at a certain frequency, and they peak while consuming less power overall to maintain it. I'm ...
0
votes
1answer
22 views

How does a film with some thickness without reflection alter a wave's phase

How does the thickness of a film alter the phase of a beam of light passing directly through the film without reflection?
1
vote
5answers
113 views

Does the statement “waves only transfer energy, not matter” violate $E=mc^2$?

I'm beginning to learn a little bit about waves, and I'm a bit confused. It is said that waves only transfer energy and not mass, but doesn't this violate $E=mc^2$?
1
vote
0answers
37 views

Can anybody explain about phase shift and phase spectrum terms in case of multidimensional signal?

I know about phase of a 1D signal, but when I move into higher dimensions like 2D or 3D etc, it becomes headache to grasp the concept. What do the terms "phase shift" and "phase spectrum" mean in ...
0
votes
3answers
52 views

How can a wave travel if it is spread over all space?

The wave equation in one-dimension is $$\nabla^2\psi = \dfrac{1}{c^2} \dfrac{\partial ^2\psi}{\partial t^2}$$ and in one dimension one possible solution to this equation is the function ...
1
vote
2answers
49 views

Would passing horizontally polarized light through a varying width vertical slit allow you to measure the amplitude of light? [duplicate]

I have found closely related questions on StackExchange, but (surprisingly) not this exact question. Seems some answers say individual photons do not have amplitude, only when traveling with other ...
-2
votes
0answers
25 views

How can we calculate the spherical wave vectors L,M,N [closed]

if we have a vector wave function in spherical coordinates ae^ikz. then how can we calculate its spherical wave vectors M,Nand L
0
votes
0answers
17 views

Finding skip distance/one-hop distance for a radio wave?

I've been racking my brains all afternoon trying to figure this out. Here's the question we're given: At an altitude of 400km is the reflective layer in the atmosphere. What is the maximum distance ...
0
votes
1answer
45 views

If EM waves are made of oscillating electric and magnetic fields, how come photons have no charge?

I just recently learned that electromagnetic waves are made of oscillating electric and magnetic fields, and I have a question. In the standard model, photons are described as having zero charge, and ...
2
votes
1answer
27 views

Is this a standing or moving wave?

The electric field of a uniform plane wave traveling in a source free region of free space is given by: $ \vec E= (0.5j \vec x + \vec y)(e^{j \beta z} - e^{-j \beta z})$. Is this a traveling wave or ...
0
votes
0answers
10 views

What is the effect of a magnetic field on a plasma speaker?

I have been doing some research for the past couple years investigating the effect of a magnetic field on a plasma speaker. More specifically, if you apply a relatively uniform magnetic field in no ...
1
vote
1answer
38 views

D'Alembert Equation and standing wave

As we know the d'Alembert Equation is $$ \frac{\partial^2\psi}{\partial x^2}=\frac{1}{c^2}\frac{\partial^2\psi}{\partial t^2} $$ for an undimentional string. Now if we seek standing wave ...
1
vote
1answer
27 views

Wave velocity dependence on frequency

Is the velocity of a wave dependent or independent of its frequency? I cannot figure this out on my own. I've asked friends and they do not know.
1
vote
0answers
21 views

Disadvantages of viewing a diffraction grating at larger order?

If you are using a diffraction grating as a spectrometer you are likely to use high order, because you have a better resolution (as a result of larger dispersion??). But are there any disadvantage? I ...
0
votes
1answer
46 views

How to get the pressure amplitude at any spatial point?

Working on the pressure equation from the linearized euler equations, I stumble across a very simple problem : How, from the pressure solution of the specific equation (see ...
3
votes
1answer
20 views

Polarisation by Reflection - oscillation direction

I'm currently studying polarisation by reflection, and have come across two pieces of information from the same source, which I can't seem to understand on how they differ. The oscillation direction ...
0
votes
1answer
33 views

Why does a good conductor shows pronounced skin effect?

I am currently studying transmission of em waves and skin effect is puzzling me. Let us consider an em wave propogating in z-direction with electric field in x-direction & magnetic field in ...
0
votes
1answer
37 views

How to compute phases of the signals?

Let us take 4 signals which are sinusoidal and periodic. Suppose you are given a phase spectrum or (/and) equation of the (main) signal only and you are said that the given (main) signal is formed of ...
0
votes
0answers
35 views

Calculating the energy of a string wave with different phase and group velocity/amplitude/etc

(Please note this is mostly a theoretical, mathematical question, not one about specific particles. Let me know if this is more appropriate in Mathematica) The energy per wavelength of an ideal ...
0
votes
1answer
66 views

Wave properties and temperature

Today it was told me that wave properties of a particle increase if the temperature decreases. I'm surprised because I have never listened a similar thing, but I think that it's very interesting. ...
1
vote
1answer
30 views

Energy Proportional to the Square of the Amplitude

I don't understand how the energy of a wave is proportional to its amplitude squared...For example, if we consider simple harmonic motion at the maximum displacement, there is no kinetic energy and ...
11
votes
2answers
517 views

Would fog impair echolocation abilities?

I was driving down a major highway today and the fog was thick enough I could barely see 40 ft in front of me. I then wondered if I had had some other form of perception could I have perceived my ...
14
votes
5answers
1k views

Do the electric and magnetic components of an electromagnetic wave really generate each other?

Frequently when EM waves are taught, it is said that the change in electric field causes a change in the magnetic field, which then causes a change in the electric field, and so on and so forth. But ...
2
votes
1answer
495 views

Wave superposition, is my textbook wrong?

Here's the question: Two coherent electromagnetic waves are incident simultaneously at some point in space. The intensity of each independent wave is $I_0$. What is the intensity of the superposition ...
2
votes
1answer
70 views

Light follows the shortest path, but to where?

I'm a high school student and I'm trying to understand why waves bend when they refract. I read a few answers on the site, and the explanation that they follow the shortest path makes sense enough to ...
2
votes
1answer
37 views

Unsmooth behavior of water waves

I happened to come across this rather interesting picture of a very deformed (or perhaps intricate) wave. The structure looks like it illustrates a superposition of multiple waveforms, as intuitively ...
0
votes
1answer
34 views

Question about group velocity and travelling waves

I'm trying to learn some basic quantum mechanics and I have a question related to group velocity of a travelling wave. I know there are already a few questions related to group velocity, but I ...
0
votes
1answer
25 views

Disparity between two texts on intensity and phase interference - which is right?

So, I'm learning phase interference. Imagine we have two waves. $$ E_1 = A_0sin(wt) $$ and $$ E_2 = A_0sin(wt+\phi) $$ With $$ \phi = \frac{2\pi}{\lambda}dsin(\theta) $$ Which is the path ...
4
votes
1answer
55 views

Speed of sound in an inifinitely dense medium

Curious thought i just had. The speed of sound is affected by a few factors, but the density plays a large role. As density increases, does this mean that sound could approach the speed of light? If ...
0
votes
1answer
45 views

How to derive path difference ($\Delta l=d\sin \theta$) for double-slit interference?

The Wikipedia page for the double-slit wave interference experiment states that the path difference between waves diffracting from the two slits is equal to: $$ \Delta l=d\sin \theta $$ where $d$ is ...
3
votes
1answer
55 views

Does Fermat's principle of least time apply to sound waves?

I am reading Feynman's presentation of Fermat's Principle of Least Time, which explains the behavior of light; does it apply to waves in general? for example sound waves or waves on the surface of ...
0
votes
0answers
27 views

Generalized long wave and KdV equation

I have read many papers about benjamin-bona-mahony (BBM) equation or Regularized Long Wave (RLW) equation and found that BBM equation can be derived from KdV equation. from other papers i got others ...
1
vote
1answer
63 views

Have we really measured the wavelength of light? [duplicate]

Have we practically measured the distances between the variations of electromagnetic radiations in space in nanometers or is it just theoritical because of calculations? Also the one who have marked ...
-1
votes
2answers
39 views

Does the velocity of a wave change after being reflected against a moving object? [closed]

This problem is from my friend ; A man is waiting for a bus. The bus is heading toward him with $v=20\dfrac{km}{h}$ To evaluate the duration, the man sent a wave with $f=880Hz$ toward the bus. ...
1
vote
3answers
45 views

General solution to the wave equation proving dependence on $x \pm vt$

I am trying to solve for a general solution to the wave function and demonstrate any solution has the form $f(x,t) = f_L (x+vt) + f_R (x-vt)$ I have used separation of variables f(x,t)=X(x)T(t) to ...
1
vote
0answers
47 views

How does light manage to change its course at the boundary of two media of different optical densities?

This is a conceptual question. I already know the law of refraction but I need something like an idea of the Physical process from both particle and wave theory standpoints. Why does a ray of light ...
0
votes
0answers
23 views

Functions of the form $F(x-ct)$ written as superposition?

In this section of the Wikipedia article on the wave equation they do the following: $$\int^{\infty}_{-\infty}s_+(\omega)e^{-i(kx+\omega t)}d\omega +\int^{\infty}_{-\infty}s_-(\omega)e^{i(kx-\omega ...