Questions tagged [harmonics]

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Calculating acceleration due to gravity using standing waves [closed]

I'm working on a lab and am trying to find an estimate for the acceleration due to gravity using standing waves. The instructions are to plot the fundamental frequency squared ($f^2$) against the ...
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Saturn's moons - getting a stable harmonic model for Mimas and Encyladus

I have built a HTML/Javascript solar system model. It is working well with real time animation. https://abetz-rouse.com.au/planetarium I don't want to get into the deficiencies of my choice of ...
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28 views

Why can harmonics be a different note than their fundamental frequency?

I was under the impression for the longest time that when you hear a harmonic on a string, its basically a sum of different resonating frequencies, which are all INTEGER multiples of the base ...
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Is being “stationary” also an example of a “periodic motion”?

I read an idea in mathematics about periodic functions that a constant function is also a periodic function with an undefinable period. So , suppose a body is at rest (for an observer). This means ...
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Are the frequencies of standing waves on a non-uniform string harmonic?

For a uniform string, the standing wave frequencies form “harmonics,” which means they are whole-number multiples of the lowest standing wave mode frequency, called the fundamental frequency. For this ...
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Inversion symmetry for Second Harmonic Generation

I read this question "Lack of inversion symmetry" in crystal?, but it is not quite clear to me how to clearly define the symmetry. Let me explain with a simple example. In the image below ...
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1answer
48 views

Why do higher frequencies tend to have a smaller amplitude than low frequencies?

Complex waves found in nature tend to have downward sloping frequency distribution. This isn't to say the fundamental always has the highest level but the general trend is that higher overtones tend ...
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47 views

Why are the harmonics of a stretched string and that of an open pipe the same?

In page-376 of the NCERT physics class-11 chapter on waves (see here), the frequency relations for the harmonic of a stretched string are derived as(eq.15.42): $$ \nu_n = \frac{nv}{L}$$ Now, in page-...
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Why are the harmonics on a string controlled by where we pluck it?

I just read this answer by rob on the question of why harmonics occur when plucking the string, in the answer I have a doubt on this point: It's worth pointing out that you have some control over ...
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Fundamental Integer Series of Transverse Waves

Can an electromagnetic wave form a harmonic series just as those of sound do? Does it requiere a vacuum or can it be done on a medium?
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Torque in a harmonically oscillating body?

The system oscillates simple harmonically And my question is will the block exert a torque on the rod with respect to the point A? Based on my understanding, Spring 1 and spring 2 both will produce ...
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2answers
51 views

Physics experiment with sound [duplicate]

I am doing an experiment for a school project which consists of blowing into 6 different bottles to create different notes/harmonics. Each bottle is filled with different volumes of water to create a ...
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2answers
111 views

During sympathetic resonance in a piano, are new frequencies generated?

Sympathetic resonance in a piano is the phenomenon of one string being excited, transmitting its sound to other strings that will then start vibrating if they have common frequencies. For example C2 ...
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101 views

Pendulum attached to an accelerating train

The question I have is similar to that of the Pendulum in an accelerating train problem. Where a bob is hung from the ceiling of a train that is at rest. The train then begins moving with an ...
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1answer
47 views

Measuring the harmonics of a vibrating string

I have a string which is vibrating at a fixed frequency, say 1 kHz. I know it is vibrating in a purely first harmonic mode because of the (sinusoidal) drive function I am using. With a microphone I ...
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1answer
25 views

Behaviour of 2 resonant tuning forks in a vacuum

The scenario is the following. Two perfectly tuned resonant tuning forks A,B are placed in the same vacuum. [ Ideally the experiment is conducted when both A&B are in free fall]. Tuning fork A is ...
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1answer
39 views

Resonance frequency of a guitar

I have some questions for you about the resonance phenomenon in a guitar: Why resonance frequency are only full integer multiples of the natural frequency, such as 2 x, 3 x, or 4 x or 3 x, 5 x, or 7 ...
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52 views

Waves and guitar frets

I have a problem to solve for Physics III at university and I can't seem to understand how to solve this question. I have the fundamental frequency at $440$ Hz, $L=1$ m, and $ρ=0.002$ kg/m. After ...
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Does electrical sawtooth wave actually produce sinusoidal oscillations at harmonic frequencies?

According to Fourier's theorem, we know that a sawtooth wave can be represented as a sum of sine waves. These sine waves we know as harmonics (in the context of sound). My understanding is that it is ...
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43 views

Harmonal density Probability changes?

I have been thinking about strings vibrating. we usually see a purely elastic string in modes of vibration as states of modes. I was thinking, what if we changed the length of the string dL such that ...
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105 views

What is the difference between $\omega$ and $\Omega$ in the equation $\Omega = \theta_o\omega\cos(\omega t +\delta)$?

The standard equation for any object moving in a linear simple harmonic motion (SHM) is $$x=A\sin(\omega t +\delta)$$ where $A$ is the amplitude, $\omega$ is the angular velocity. Likewise, converting ...
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29 views

Laplace transform for damped waves

In Zeidler's book on QFT, page 94 there is a definition for a Laplace transform that reads \begin{equation} (\mathcal{L} f)(\mathcal{E}) = \int_0^\infty e^{i\mathcal{E}t/\hbar}f(t) dt, \end{equation} ...
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Why do higher harmonics have a lower amplitude than the fundamental frequency?

When we pluck a string, it vibrates in all possible modes of vibrations. The lowest frequency possible is the fundamental frequency and it is the most significant part of sound. But why do the ...
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1answer
99 views

Question regarding open and closed air columns

I'm studying high school physics and I've encountered this question: An air column that is open at both ends has a distance of 24.0 cm from one resonant length to another. What is the wavelength ...
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1answer
816 views

Why are there no even harmonics in a closed pipe?

I have seen a diagram on sites such as hyperphysics.com that show that there is a missing bit every time so that it makes every harmonic odd. I was hoping I could get a more intuitive explanation. We ...
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112 views

Relation between frequencies of different harmonies

I know the relation between frequencies of different harmonies is $$ f_n = n\times f_1 $$ but I'm heving trouble to develope the equation which proves this equality. can anyone please give me a lead ...
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1answer
15 views

How do cavity resonators differ from tubes of uniform width?

I read that wine bottle produces sound when u blow sideways onto its rim because some frequencies of the white noise produced in your mouth gets amplified when they match the natural frequency of the ...
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1answer
45 views

Finding the conditions for a resonant (unique single mode) state in the wave equation

If we have a string of length $L$ in constant tension $T$ and we oscillate one of the extremes at the rate $\sin{\frac{\pi nc t}{L}}$, we observe in a lab that single harmonics are produced. I want to ...
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1answer
154 views

What is the relation between the fundamental frequency and a harmonic?

I am currently busy with a physics report about determining the speed of sound in air. In order to do this, I was told to use a tube that can extend or shorten in order to find the different harmonics ...
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1answer
41 views

What causes this high frequency “noise” in HHG spectra?

Looking at high harmonic spectra, one can often see that peaks corresponding to higher harmonics look more and more noisy and seem to be drowned out by the noise. For example, one such spectrum is ...
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Are there any resonant frequency spectra that do not possess any harmonics?

I’m hoping that somebody can help clarify the following passage regarding standing waves and the systems that support them: Many systems that support standing waves have resonant frequency spectra ...
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1answer
489 views

Resonant frequencies in organ pipes

I have a series of doubts regarding the principle of organ pipes. For a given length of closed organ pipe there are various modes of vibration for the standing waves.I dont know if this is silly but ...
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17 views

Dependance of number of harmonics from force of collision

I recently found out that if hit something hard, it will produce all harmonics, but if hit with less and less force firstly low harmonics will disappear firstly and only high will stay. Why so?
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1answer
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Why are planet's maximal/minimal angular speed ratio harmonic?

See this Wikipedia page for Harmonices Mundi, a book by Kepler (yes, he was the one to discover the three Kepler's laws). The author writes: He found that the difference between the maximum and ...
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Why coupled oscillators tend to seek integer frequency ratios?

In this document, the author writes (page 225) Coupled oscillators have a tendency to seek frequency ratios which can be expressed as rational numbers with small numerators and denominators. For ...
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Is there a way to know the non-zero coefficient of $\cot(\theta)$ expansion in spherical harmonics?

I'm currently trying to find an analytical solution to the Poisson equation for a given distribution using a multipole expansion. During this task, I found the radial expansion and everything else, ...
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111 views

How many linear combinations of harmonics or normal modes can describe the same periodic function as a Fourier series?

Please note that I am not asking how many terms in a linear combination can describe a specific periodic function but if given that there exist a set or linear combination of normal modes that ...
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Why can an inner product of an eigenvector also be used as an eigenvector?

In quote box below, there is an inner product of an angular momentum eigenvector. Why can you use this inner product as a new eigenvector for the next part of the work? And why do they "of course" ...
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Why a musical instrument's string oscillates with many frequencies? [duplicate]

I am trying to understand why when we play a note on a stringed instrument, not only it oscillates with it's fundamental frequency but also the multiples of that. For instance if you play a D on the ...
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1answer
147 views

Harmonics in a tube closed at one end

I have been learning about sound and how a tube closed at one end only seems to have odd harmonics. However, I have found that although clarinet follows this and plays only odd harmonics, saxophone ...
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1answer
503 views

De Broglie explanation of Bohr's second postulate. discrepancy of 2 times?

I am reading how de Broglie justified the 2nd postulate of Niels Bohr (i.e. angular momentum of an electron to be integral multiple of $\frac{h}{2\pi}$). I get his explanation of electron acting like ...
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188 views

Why the faster you spin the highest the pitch get in a whirly tube? [duplicate]

I would like to understand why the faster you spin, higher normal modes are excited This is the tube i'm talking about, i think it's used as a kid's toy: https://www.youtube.com/watch?v=eCOZxzO3FvE ...
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sounds of polygonal ring chimes of metal

Suppose we have a number of rings, each of them is constructed from some mass of wrought iron or steel: each ring is a polygon, which I would like to suppose is constructed without welding (so they ...
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1answer
110 views

Integer multiples of fundamental time period? [closed]

If we define harmonics to be positive integer multiple of fundamental frequency What will we say to positive integer multiples of fundamental period?
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Is the first harmonic the prevalent frequency? [closed]

Why, when we play a string, almost all of the energy we give them is ''used'' in the first harmonic (the fundamental frequency) rather than be distributed between all of them?
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If all harmonics are generated by plucking, how does a guitar string produce a pure frequency sound?

A guitar is a plucked instrument and it is played by plucking a string at an off-centre point fixed at two ends. In general, Fourier analysis tells that all harmonics (the resonant frequencies of the ...
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Why are there these other “harmonics” (violin-specific terminology) in violins?

I've often read explanations of how standing waves form on the string of a violin and their harmonics but there is another phenomenon I've never seen explained: When you play certain notes, musicians ...
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Why, in an open or half-open pipe, must an open end of a standing sound wave have a pressure of zero?

I believe this question was asked in some form before, but I'm not clear on the answer. If a sound wave must equal air pressure when it exits a tube, why is it possible that at many points after the ...
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166 views

Pulling a string with both ends fixed [duplicate]

Consider a string with both ends fixed. If somewhere in middle of it be pulled and released, how would it oscillate and what is it's equation? My solution assuming the result is a standing wave: The ...
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How is it possible that multiple overtones can exist at the same time?

I was wondering how it is possible for overtones to co-exist at the same time. When one pulls a string, it starts to oscillate and forms a standing wave with frequency $$f_0 = f$$ Additionally, ...