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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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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27 views

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

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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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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38 views

What is the relative speed of the galaxy with respect to the Earth [closed]

Consider a distant galaxy. Though this is a bit contrived, suppose that an astronomer measures the fourth transition of the Brackett series of transitions from n > 4 to n = 4 in Hydrogen at a ...
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40 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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49 views

Diffraction to be explained without Huygens principle

Can we explain diffraction without using Huygens principle?
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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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13 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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21 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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24 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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84 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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277 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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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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18 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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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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14 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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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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19 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
47 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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63 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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26 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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19 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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211 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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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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34 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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15 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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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 ...
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46 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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25 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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26 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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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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35 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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60 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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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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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 ...
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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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22 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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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 ...
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65 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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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 ...
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41 views

What are overtones and how do they relate to harmonics?

Problem 43. Two organ pipes, a pipe of fundamental frequency 440 Hz, closed at one end, and a pipe of fundamental frequency 660 Hz, open at both ends, produce overtones. Which choice below ...
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Oscillation of air particles and speed of sound wave

A sound wave is essentially air particles oscillating parallel to the direction of travel of the wave. We learnt that $v = f\lambda$, where $v$ is the speed of the wave, $f$ is the frequency of the ...
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43 views

Why are speakers louder in a corner?

You can test this very easily using an iPhone's speaker pointed towards a wall. When the speaker is more than an inch or two away, it is normal volume. However, when the speaker is nearly touching the ...
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26 views

Finding the distance between two osclilating particles in a wave

Assume a wave function $\psi = \psi(x,t)$ where $x$ is position from the starting point $(0,0)$ and $t$ is time. Two oscillating points A and B are located at $x_1$ and $x_2$ respectively with $x_2 ...
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43 views

How does underwater sound sound?

I have been thinking about underwater sounds (i.e. sounds produced and recorded underwater), what exactly the water does, and how to emulate this effect. Imagine a sound played underwater (e.g. from ...
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28 views

Proving standing waves equation for open-open pattern [closed]

My teacher assigned me to prove open-closed and closed-closed standing waves patterns using math. With closed-closed, it was fairly easy: $$\begin{align} D(x=0,t)&=0\\ D(x=L,t)&=0=2A\sin(kx) ...
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69 views

Do waves accelerate?

Typically we think of acceleration as a particulate property but a previous question on this forum got me thinking. If we think of a wave increasing its velocity by increasing its energy/frequency ...
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19 views

Sound system and Temperature Effects

You arrange a patio with a sound system. Ignore all sound reflections. If you are at a certain location on the patio, you can find the two lowest frequencies you will experience total destructive ...
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Speakers and Changes in Temperature

Let's say that there is a speaker that oscillates the same way. Now, let's say there is a sudden drop in temperature. I know the speed of sound would drop. But, what will drop, the wavelength or the ...