Questions tagged [resonance]

Resonance is a characteristic of physical systems having a structure that allows energy to flow between various states at a specific, oscillatory rate (resonant frequency). For a stable resonant system at steady state the internal energy is either fixed without losses or the rate of energy input is equal to the energy losses.

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210 views

What is the waveform for a Rubens' tube driven slightly off-resonance?

This video has a nice description of resonance inside a Rubens' tube, and it has some pretty nice visuals of the tube being driven at the precise resonance, as well as just above resonance: I rather ...
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How is Mössbauer spectroscopy so resistant to thermal motion?

Mössbauer spectroscopy detects tiny shifts (on the order of $\rm{\mu eV}$ or $\rm{meV}$) in a gamma ray's energy due to the chemical environment of the nucleus. The scan consists of moving a source ...
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365 views

Driven Pendulum

If the point of suspension of a pendulum is driven periodically in the vertical direction , we can derive the equation of motion for the suspended mass to be of the form, $\ddot{\theta}(t) + (a-b\cos{...
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81 views

Swing: why does the body position modify the amplitude?

When a person swings, why does the amplitude of oscillations increase if the person changes the body position ? That is, when descending and approaching the vertical position, if the person extend his ...
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382 views

How do I calculate the resonance frequency of a block of material?

I would like to know how I go about calculating the resonance frequency for an object, given its material properties and dimensions. For example, a small rectangle $X$ by $Y$ by $Z$ dimensions, I ...
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56 views

Why do scattered waves vanish when the wavenumber of the incident wave is an eigenvalue of the interior Dirichlet problem. Where has the energy gone?

I normally work with numerical computations for wave scattering, but I am now trying get a better understanding of the physical processes underlying the theory, in particular what happens to the ...
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76 views

Why would oscillation of a gas column inhibit rather than promote mixing?

Many years ago I helped to support an experiment conducted in Japan which investigated the effects of high frequency oscillation ventilation (HFOV) on the mixing and distribution of gas into the lungs....
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710 views

What is the mechanism of subharmonic oscillations?

It's clear to me from linear systems theory that energy manifested within a fundamental mode of resonance can saturate with the excess energy spilling over into harmonic frequencies greater than the ...
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246 views

Metastable bound state in resonance scattering

In resonance scattering, why does the mean lifetime of the "metastable" bound state depend inversely on the width of the resonance?
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2k views

Chladni Plate Mathematics

I am a high school student doing an IB Extended Essay investigation concerning the resonant frequencies of Chladni plates of differing materials and sizes. Would someone please explain the definition ...
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86 views

Is resonance an energy eigenstate?

In the particle physics book of Martin & Shaw, they used QM to derive the decay distribution, namely, breit wigner formula. What confused me was that, here they assumed the resonance state $\psi_0 ...
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Does putting a part under stress change its natural frequency?

It is easy to imagine how tension changes the natural frequency of a wire. Intuitively it happens with a guitar string when you bend the neck. However, does putting a beam under stress (internal or ...
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51 views

How is “linewidth” defined for a damped driven oscillator?

Suppose we have a damped driven harmonic oscillator governed by the following equation of motion: $$\ddot \phi(t) + 2 \beta \dot \phi(t) + \omega_0^2 \phi(t) = J(t) \, .$$ In the case that $J(t) = A \...
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What are the conditions for molecular,photon resonance other than same frequency?

I know that the basic condition for molecular,photon resonance is same frequency but what are the other condition for this process like phase relationship,round trip of the molecules and so.Also can ...
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1answer
46 views

What are all the possible ways to achieve acoustic resonance in a cavity?

If one were to observe acoustic resonance in a cavity (semi-closed volume of space) what is the complete list of potential hypotheses as to the cause? In my limited experience I can list the ...
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1answer
58 views

Renormalising $\Delta$ baryon mass in chiral effective field theory

I have essentially no experience of quantum field theory, other than a superficial knowledge of some basic ideas - my apologies if I've phrased anything unusually or made any mistakes in my question ...
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1answer
96 views

Boundary condition on $\mathbf{B}$ to describe resonant cavities from waveguides

In Jackson- Classical Electrodynamics when resonant cavities are discussed (8.6, page 252) (but also at page 7 here or at page 19 here) the explanation is made by saying that the solution is the same ...
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184 views

Standing spherical wave solution

Let's say we have a spherically symmetric light wave $u(r,t,\theta,\phi)= u(r,t)$ that satisfies the following wave equation with spherically symmetric potential $V(r)=2/r^2$ (also set $c= 1$ so $\...
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3answers
173 views

Can I shorten the resonant length of a tight wire by moving its endpoint in phase ?

A stretched string, tube or wireless antenna has a resonance fixed by the velocity of the wave (sound in air, metal, electrical wave etc.) and the length of the object. The fundamental occurs when a ...
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80 views

How does a “Haskell Resonator” work?

I would like a simple explanation of how a "Haskell Resonator" works. You may assume that I understand the Wikipedia paragraphs on open and closed resonator cylinders. Exactly how does placement of ...
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1answer
137 views

What is the physical interpretation of imaginary terms in the neutron optical potential model?

I'm doing a computational project on neutron scattering and I've found that if you simulate (n,n) collisions on Uranium 238, the program predicts resonances not found in experimental data. The ...
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133 views

Bound state of $\mu^- \mu^+$ . Why non-relativistic muon states?

Peskin & Schroeber page 148 discuss the creation of a $ \mu^+ \mu^-$ resonance state . Equation (5.44) describes the creation of a Spin Up bound $ \mu^+ \mu^-$: $$ \mathcal{M} = \sqrt{2M} \int \...
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Is there a resonance within the earth, separate from the Schuman resonance?

In a very recent biography of Nikola Tesla by Bernard Carlson, the author explains that Tesla measured the resonant frequency of the earth using his invention - the amplifying transmitter. Tesla came ...
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1answer
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Why in particle physics the background of resonance is a decaying exponential?

When in particle physics they plot the mass histogram we see a resonance on top of a decaying exponential background? Why is the background modeled to be that way? what is the physical explanation? ...
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441 views

Resonance condition in confocal cavity

In a confocal cavity, a beam traverses the length of the resonator 4 times between two transmissions along the same ray. . For example, in the above figure, path difference between two beams that ...
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223 views

Reflector Klystron and Isolator for ESR/EPR Experiment

I am doing a lab on ESR/EPR, and I would like to know how the reflector klystron operates. It is very old and the company who made our model does not exist anymore and there are no operation manuals. ...
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70 views

Is there an equation that tells you more about the amplitude of an object which is in resonance?

I'm a high school senior and I have to write a paper about resonance and differential equations. I've been searching the Internet for a long time, but I haven't found an equation that is properly ...
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21 views

Electron spin resonance

What is the principle of electron spin resonance? I'm performing an experiment in which I've a DPPH(paramagnetic) sample and I'm trying to find out the lande's factor using ESR setup. My problem is I'...
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44 views

Resonance and energy flow

In this post, Alfred Centauri describes the resonance as a phenomenon which appears when 'the energy flow from the driving source is unidirectional' and then shows that this is the case for $\Omega=\...
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2answers
47 views

Electromagnet produces sound from hollow pipe

I have wrapped around a 80cm metal pipe some copper wire and attempted to produce an electromagnet. The electromagnet works nonetheless from the extremities of the metal pipe a sound is being produced ...
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1answer
69 views

Why are higher frequencies amplified less by filling a bottle with warmer water instead of colder water?

Out of curiosity I was trying to figure out what makes the sound of hot water versus cold water filling a bottle different, but I'm unable to find any explanation as to why such differences occur. ...
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57 views

Faraday waves and Chladni plates

I am a High school student who's writing a research paper about Faraday waves and Chladni plates. I've been doing a lot of research on Faraday waves specifically, as there aren't many sources that can ...
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1answer
89 views

Chladni Patterns (Length Factor)

I've recently been conducting experiments on the Chladni Plates, testing out how the length of a square Chladni plate (and consequently its area) affects the frequency at which each respective chladni ...
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3answers
94 views

$Q$-factor for damped oscillator (not driven)?

How would this be defined? Some of the Q-factor definitions I have encountered include: $$Q=2\pi\frac{Energy \space stored}{Mean \space power \space per \space cycle}\\Q=2\pi\frac{Energy \space ...
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What is the mathematical basis behind using a chirp signal to determine the resonant frequency of a second order differential system?

It is a common practise for engineers to try to determine the resonant frequency of a system through a chirp signal. Given a damped oscillating system with displacement $x$, driven by a chirp signal ...
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260 views

How is sound produced in pea whistles? (I think they're called police whistles in the US.)

I read the topic called 'Whistle Physics' on this forum. From what I gathered there, @alephzero seemed to be saying that changes in air pressure cause air to be alternately sucked in and pushed out of ...
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59 views

Air flow through a penny whistle

I am confused about exactly how air flows through a penny whistle. I would also like to double check that I understand correctly what the cavity of resonance is. Say I have a whistle like this: <...
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Measuring time in the photoelectric effect

Consider the following hypothetical: An atom is traveling with a velocity of v to the left, directly towards an incoming photon, as crudely depicted below. p----> <----A Question (1): What is ...
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123 views

What 2d shapes would have the most resonant frequencies?

A square Chladni plate has a handful of resonant frequencies in the audio range. If you wanted to make a plate with very many (infinite?) resonant frequencies, what shape would be best? You wouldn't ...
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44 views

Model for sound generated by air flowing through pipe

I'm trying to write a program simulating the sound of an petrol car engine, just for fun. As a part of this, I'm trying to model the sound of air escaping the combustion chamber through an open ...
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36 views

overstability vs resonance: what is the difference?

Reading about discs, I encountered the word 'overstability' that its difference with resonance is not clear to me. Does anyone know the difference?
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34 views

Aerogel resonator

I'd like to find an approximate relationship between the peak velocity for an aerogel resonator, resonating at (angular) frequency $\omega$, and the amplitude of motion. Essentially the fact it's ...
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0answers
55 views

What is the effect of a pair of different sounds or frequencies upon an object?

I am new to learning about the physics of sound, resonance, resonant frequency, and standing waves. Most of the sources I am reading describe the effect of a single frequency on an object when that ...
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99 views

Modeling the field inside a cavity resonator

As part of the design of an experiment, I am trying to model the magnetic fields inside a hollow rectangular waveguide cavity. I have not had any problems calculating the cavity physical dimensions ...
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256 views

How to modify Breit-Wigner resonance formula in case of a nearby threshold?

When calculating the scattering cross-section via the resonance with mass $M$ one can use the Breit-Wigner formula \begin{equation}\frac{1}{s-M^2+iM\Gamma},\end{equation} where $\Gamma$ is the ...
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1answer
75 views

Does resonator will always dampen the driving oscillator?

I was doing a question about resonance of sound box connecting to a tuning fork. It asks why the sound lasts for a shorter time with sound box than if the tuning fork is struck identically without the ...
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Why does scratching a blackboard gives such a painful noise?

I think we all have heard that terrible sound coming from scratching a blackboard with your nails. How is it produced? Has it something to do with the length of our nails?
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What is Lamè mode?

I am trying to read some of the articles that says Lamè mode. But I can't find in google that describes Lamè mode. Can anyone quote good reference for this term?
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215 views

LCR circuit at resonance

I am studying about the LCR circuit and have a question regarding potential difference across inductor and capacitor. From the thing I have studied I came to know about that potential across inductor ...
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19 views

Optical Delay Lines

Why does the peak group delay for an add-drop ring resonator's drop port reduces to 1/4th of that of an all-pass ring resonator? Shouldn't it just be half of its value as the transit length is ...