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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37 views

Why are C, G and C all played open on the trumpet?

Why are C, G and C all played open on the trumpet? I would expect C, F# and C to be produced by adjusting embouchure as they're evenly each a half octave apart. What am I missing?
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The value of the driving frequency at which the voltage across the capacitor becomes maximum in a series RLC ac fed circuit

The circuit diagram is as shown. As per the book voltage across the capacitor is maximum during resonance that is p=1/√(LC) But what I found out is a bit different . And it is. p=√((1/LC)-(R²/2L²)) ...
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183 views

Where do pure tones occur in nature, besides harmonics?

When you sound a tuning fork, you hear an pure tone/sine wave of usually 440Hz. Yesterday, I tried hitting a table knife made entirely from stainless steel against a grapefruit. When I held it up to ...
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Why do the matrices in k-space and the final MRI image have to match?

Naturally, there is no correspondence pixel-to-pixel between Fourier space (k-space) and the final 2D image of an MRI - k-space stores the Fourier coefficients, hence each pixel in it affects the ...
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Are These Guitar Strings Demonstrating Subharmonics?

This video has a fair few instances where there is an exaggerated wiggling of the guitar strings. I rationalise this by saying its a similar effect to rotoscoping, like where wheels appear to spin ...
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187 views

Why don't transformers have capacitors?

I recently learnt about how resonance in an LC (inductor capacitor) circuit could increase the efficiency of the circuit, for application in something like Resonant Inductive Power Transfer. Excuse ...
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73 views

Feshbach resonance and the Gross-Pitaevskii equation

I have a question about Feshbach resonance and the (generalized) Gross-Pitaevskii equation. If we consider a BEC at a finite temperature $T_{BEC}$ and a static mean-field thermal cloud at temperature $...
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59 views

Relation between shapes and vibrations

I have observed the following shape on surface of water when the bottle was standing on a cooling water machine. I was amazed by the formation because I had not seen this before. I'm not completely ...
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What does resonant frequency in the Q factor mean?

For the Q factor of a body undergoing force oscillations, does resonant frequency refers to the frequency of driving frequency or the body's natural frequency? The term resonant frequency seems to ...
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Musical Instrument that Exhibits Spherical Harmonics

A guitar string exhibits standing wave patterns when its struck, some superposition of sines and cosines, a drum head exhibits a superposition of Bessel functions when its struck. Is there any ...
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2k views

Why are there only odd numbered harmonics in one closed end resonant tube? [closed]

Why do we only have odd numbered harmonics at one-end closed tubes, however, if we do a frequency spectrum we have some periodic spikes between the odd harmonic spikes, just like the picture below ...
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Why is the Laplace Transform essentially never used when dealing with problems involving resonance?

Both the Laplace Transform and the Fourier Transform can be applied to a PDE, for example the wave equation, and used to derive a solution to the equation. But I never see the Laplace Transform used ...
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Resonances in QFT

I am a bit confused about resonances in QFT. I am reading Schwarz's QFT book and as far as I understand, if in a reaction the mass of the particle acting as a propagator is bigger than the sum of the ...
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130 views

Quantum tunneling/transmission through an infinite potential

In Shankar exercise 5.4.2 we consider the reflection and transmission of a wavefunction through a delta potential $V(x) = aV_0\delta(x)$. I understand that to mean that the potential is zero ...
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51 views

What is a correct loudspeaker connecting scheme and why? [closed]

Thinking of "what would be best shape for a subwoofer box?" i came to idea of a barrel, with its sides (or covers) "replaced" with speakers: I have stereo bass amplifier which is fed from single ...
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583 views

Why does the length of a pendulum cause different natural frequencies of pendulums in Barton's pendulum?

In Barton's pendulum, the pendulum with string that is the same length, L, as the brass bob (source of driving frequency) has natural frequency equals to the bob's driving frequency. The pendulum ...
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32 views

Why is $Q$ factor an important quantity for electrical oscillations transmitting radio waves?

My textbook says that "$Q$ factor is an especially important quantity for electrical ossicilations trasnmitting radio waves. When selecting radio and television stations it is essential that the ...
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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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Uncertainty cannot be calculated?

I'm doing an experiment on resonance. The phase difference between the driving force and the one oscillating is given by $$\varphi=\arcsin\left(\frac{y_1}{y_2}\right)$$ where $y_1$ and $y_2$ are ...
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156 views

Dispersive regime and resonator frequency pull

I have come across terms such as "dispersive regime" and "dispersive measurement" often. To understand this, I have been reading this, this, and this. In the first paper, the gist I got is the ...
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Does the resonance frequency of a cantilever beam depend on whether it is bending in-plane?

What is the in-plane resonance frequency equation for a single-beam cantilever of rectangular cross-section that is fixed on one end and has a mass M attached to the other end? Below are the only ...
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3answers
258 views

What is a complex phase shift?

In a complex methods course I am taking, we were given an equation for a particular driven harmonic oscillator where the driving force is trigonometric. I have worked out the math and obtained an ...
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251 views

What is the difference between natural, fundamental, resonant, and forced frequencies?

I'm just overall slightly confused on their exact definitions, as they get thrown around a lot.
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How LC oscillator is used for generating signals?

I have been trying to understand some practical applications of LC oscialltors and I dont seem to find much information available on net. One consistent application that I see is "LC circuits are used ...
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179 views

What happens in an organ pipe at frequencies other than the harmonics?

I learned that, at frequencies corresponding to harmonics, standing waves are formed. But what actually happens at other frequencies? Won't the reflected wave superimpose with the original wave? Do ...
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316 views

What is the effect of mass on resonance amplitude?

When a system is undergoing forced oscillations, why does reducing the mass of the system cause the frequency response curve to shift downwards? I encountered this problem in a practice paper, but I ...
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250 views

Can vibrations be used to reduce friction?

This lecture by Julius Miller got me wondering if acoustic resonance (or vibration in general) can be used to reduce friction (or stiction). The answer seems to be no based on the observation that my ...
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How does a driving frequency induce resonance if it is not exactly equal to the natural frequency?

To my understanding when the driving frequency is equal to the natural/resonant frequency of the object, there is constructive interference between the oscillations of the object and driving force. ...
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104 views

Are resonances formed in scattering between a baryon and meson?

Consider the following reaction of strong interaction (in a scattering process) $$n+\pi^+\to \Lambda_0+K^+\tag{1}$$ Then the particle $\Lambda_0$ formed decays with weak interaction $$\Lambda_0\to ...
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165 views

What is the relationship between excitation and resonance?

From Resonance (particle physics) - Wikipedia: In particle physics, a resonance is the peak located around a certain energy found in differential cross sections of scattering experiments. These ...
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96 views

Time evolution of state in rotating B-field spin system

I'm given a state $|\psi(t)\rangle$ that solves the time dependent Schroedinger equation with the Hamilton operator $\hat{H}(t)$. $\hat{H}(t)$ describes a Spin-$\frac{1}{2}$ in a rotating magnetic ...
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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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243 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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Why are the nodes of an open tubular bell located at .224*L instead of .25*L?

Say that we have a tube of length $L$. In the tube, there is a standing wave of wavelength $\lambda$. Then, $L=\lambda$. $\hspace{2.5cm}$ In the above diagram, the wave's amplitude is highest at ...
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85 views

Resonance and modes

I use a metal body (let's say cooking pot) in which I induce eddy current via induction at certain frequency which I can change as I wish. Every object has it's own accustic resonant frequency. If ...
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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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What is the geometry of DeBroglie standing waves?

I asked a similar question here . But never received a complete answer. So I've made the question more specific to DeBroglie waves. So from what I've read DeBroglie waves are indeed standing waves ...
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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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204 views

Designing a high-$Q$ RLC circuit

I would like to make a series RLC circuit which will serve as RF receiver. I would like very high frequency selectivity, i.e. narrow bandwidth, i.e. $\pm$200 Hz. The sharpness of a resonance is ...
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54 views

Is my understanding of standing wave resonance satisfactory in this exercise?

As the title suggests, I'm wondering how I handled the following exercise checks out: A loudspeaker is placed close to one end of a pipe that is open at both ends. The loudspeaker is driven by a ...
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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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The Helmholtz resonator, what's actually resonating?

I'm trying to more closely understand the physical mechanism behind the Helmholtz resonator. If I model the resonator in terms of an analogous series linear electrical circuit: resistance ($R$), ...
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Is there a resonance frequency to air itself?

Obviously a lot of things cause air to vibrate, but does air have an actual resonance frequency?
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How to reconcile infinite cross section of resonances with cross section formula from quantum mechanics?

If we consider $s$-wave scattering for two scalar fields $\phi$ and $\chi$ with an interaction $\frac{g}{2}\phi^2\chi$, then the Lorentz-invariant scattering amplitude to second order is: $\mathcal{M}...
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Air oscillation at open window of a moving car

When driving a car with an open window one can hear (and feel) oscillations of air at the threshold of the open window. I used to think the open window and the car interior were forming a Helmholtz ...
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231 views

mode-locked laser Repetition Rate

I don't understand how we can produce a laser system with different (lower) repetition rate than the resonant frequency of the cavity? In other words, when we have different resonating modes, then ...
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599 views

The “watering hole” frequency versus microwave oven frequency

I recently learned about the "watering hole," a group of frequencies between 1.42 and 1.66 GHz. I also read that microwave ovens operate at 2.4 GHz. If 21 to 18 cm (1.42 to 1.66 GHz) is the resonant ...
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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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782 views

Why do piezoelectric elements have a resonant frequency?

While working with a piezoelectric element, I noticed some high frequency oscillations at 6kHz. I can't figure out why the piezo element has a resonant frequency. This is unlikely to be noise as there ...