# Tag Info

### Why do we hear frequencies in the basis of sine waves?

To put your question in a wider perspective: consider white noise As we know: the expression 'white noise' is used for continuous sound that consists of random frequencies; random shifting of ...
• 15.4k

### Why do we hear frequencies in the basis of sine waves?

The human sensory system is a large ensemble of detectors which are made of nerve cells. A complex sensation occurs when a stimulus triggers a large number of nerve cells, while a simple sensation ...
• 71.8k

### Why do we hear frequencies in the basis of sine waves?

The "reason" that the Fourier decomposition is the "correct" one has to do with the fact that both signal detectors (microphones, ears, etc.) operate as driven harmonic oscillators....
• 4,242

### Why do we hear frequencies in the basis of sine waves?

We can and do in some cases. Take a look at the Zernike Polynomials for decomposing 2-dimensional frequency distributions, for example. The short answer is that sine waves are nice and clean, behave ...
• 10.6k

### Is wavelenth of a particle relative according to Wave Particle Duality?

This is indeed counter intuitive, but then again quantities like kinetic energy also aren't conserved when you transform frames. For a consistent treatment you can have a look at the Klein-Gordon ...
Accepted

### Is wavelenth of a particle relative according to Wave Particle Duality?

The de Broglie relation is a forerunner of the quantum mechanical wave equations. We now know that the wavelength in the wave particle duality is not a wavelength in space. It is the wavelength of the ...
• 222k
1 vote

### Does the "particle in a box" necessarily form a standing wave?

No. Any "suitably well-behaved" function $\psi_x$ can be the wave function of the particle in a box (infinite well version) provided that it is zero both at and outside the walls of the box. ...
• 17.3k

### What is the potential energy of electromagnetic waves traveling in air?

Potential energy is not an intrinsic quantity of any physical object, and therefore it is not meaningful to ask of the potential energy of an electromagnetic wave. In some sense, you can view the EM ...
• 61
1 vote
Accepted

### How to distinguish between zeroth, second and higher order sounds?

All these modes are oscillations in the conserved densities (particle number, energy, momentum, etc.) of an interacting many-body system in approximate thermal equilibrium. Consider first ordinary (...
• 17.1k

### Does the "particle in a box" necessarily form a standing wave?

It is completely possible for a particle in a box not to be in a standing wave state. In fact there are infinitely many more non-standing wave solutions to the particle in the box than there are ...
• 4,087

### Does the "particle in a box" necessarily form a standing wave?

It’s important to make a distinction between two different “particle in a box” setups. 1.) Infinite Potential Well Imagine that the “box” is a region with $0$ potential energy, and everywhere outside ...
• 378

### Does the "particle in a box" necessarily form a standing wave?

The particle in a box does not necessarily form a standing wave. In fact in quantum mechanics these are states of definite energy that have trivial time evolution, but superpositions of them have non-...
• 35k

### Wind and sound waves

The curving pattern is not the only difference between (a) and (c). Look at the density of the rays coming from the source. In (a), it shows that the leftward wind would create a higher density of ...
• 56
1 vote
Accepted

If we assume time-harmonic signals, then we may write (as @Prahar suggests) $$\psi(r,t)=e^{-i\omega t}f(r).$$ Substituting this into the $N$D wave equation yields the $N$D Helmholtz equation: $$f'' + \... • 1,392 0 votes ### Two waves of frequencies 2kHz and 2.1kHz are traveling in the same direction. Will they produce beats? If you combine (for example by applying them to the same detector) two waves with different frequencies, they will produce beats. Noise is a random variation of a signal variable. If your two waves ... • 23k 1 vote ### Does a tower bell ringing prevent thunderstorms? The energy scale of thunderstorm is much larger than that of a bell (most other devices built by humans), so it is unlikely that such devices can affect thunderstorms in a controllable way. A single ... • 1,778 0 votes ### How to solve the Helmholtz equation in damped oscillator BCs? Short answer: Replace \omega with \omega-i\xi. Longer Answer: The Helmholtz equation is derived from the wave equation, which may be written as$$\nabla^2P -\frac{1}{c^2}\frac{\partial^2P}{\...
• 1,392

You can compare this to taking the mean of a random sample of mean zero random variables. Some observations will be positive, and some will be negative, and so there will be a lot of canceling. ...
• 8,158

### How to Model Chirp in Laser Pulse

Firstly, in your code you are confusing wavelength with frequency. You defined $\omega_0$ as 1µm. That is a typical wavelength ($\lambda$). $\omega=\frac{2\pi c}{\lambda}$ For 1µm wavelengths you need ...
• 883
Accepted

### Can the dynamic between high speed sound media and slow one preduce shock wave?

Yes- sort of. High-speed movies of nuclear explosions near the ground show that the shock wave travels faster in earth than in air. The disturbed earth then begins to propagate an acoustic pulse up ...
• 73.8k

Since the phases are random, the waves do not add coherently... but neither do they cancel coherently. Furthermore, loudness is really a measure of the intensity of the sound. Thus, if we consider a ...
• 39.3k

### The 1D wave equation with gravity and the catenary

See Time Independent and Time Dependent Catenary Problem, a short paper that includes diagrams and derivations and behind some of what probably_someone posted.
• 101
1 vote

### Maximum oscilations of air molecules

What you are most likely referring to is an acoustic standing wave, and asking whether the air molecule velocity is highest at pressure nodes. The short answer to this is, yes, the air molecule ...
• 2,831
Accepted

### Is there an electromagnetic analogue of thermoacoustics?

Yes, you are describing a waveguide which is a pipe that is used to conduct microwaves. It is possible to build standing electromagnetic waves inside such a pipe, giving rise to the klystron and ...
• 73.8k
Accepted

### Why the amplitude of monopole solution in Helmholtz equation is complex?

If there is a single monopole it does not matter whether $A$ is real or not but if you have two or more sources then their relative phases, and thus the phase of $A$, do matter. The same holds if the ...
• 9,700