# Tagged Questions

Frequency is the rate of repetitive aspect in the amplitude over a given dimension.

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### How would I calculate the frequency of the sound produced by a bowed glass plate?

I'm working on a project that involves getting a note to sound from a glass plate by bowing its edge with a violin bow. I'm trying to work out exactly what frequency I'll get from a piece of glass of ...
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### Why does public mains power use 50-60 Hz and 100-240 V?

Is there a physical reason behind the frequency and voltage in the mains electricity? I do not want to know why exactly a certain value was chosen; I am rather interested to know why that range/order ...
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### Pitch and loudness relation

Using an Oscillator in a program, I noticed that the lower and the higher frequencies are less loud than the middle ones. I suspect there is a relation between pitch and loudness but can it be ...
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### Finding the range of frequencies to which a receiver should be set

I'm working on a study guide for a test for my Modern Physics class, and ran across a question I'm having trouble with. A radar transmitter emits a pulse of EM radiation with ...
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### Must a universal motor always rotate at the frequency of the AC current?

So here I have a picture of a motor (I think it is a universal motor but I am not sure). My question is if this motor is connected to an A.C. supply, does it have to rotate at the frequency of the ...
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### Tuning the frequency in graphene

As is well known, the frequency of transverse optical phonons in single layer graphene ranges from $10^{11}$ to $10^{12}$ Hertz. How can one "tune" the frequency to a specific value?
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### Relation between frequency and intensity of light

I was going through a question in photoelectric effect and it was a true/false which says that the intensity of the incident light gets doubled on doubling the frequency. The answer is given as true ...
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### Energy corresponding to the peak of velocity power spectrum

I ran a MD simulation for a number of N molecular hydrogen. I used the velocity time history of system for each atom and subtract the velocity of center of mass of each molecule from the velocity of ...
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### How energy of a photon or EM wave has something to do with frequency?

While I was thinking what exactly meant by energy in quantum mechanics, I was quite shocked by the fact that it is proportional to frequency. $$E=hf$$ Given the fundamental definition of energy in ...
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### Why do 2.4GHz frequencies offer greater range than 5GHz routers?

I would've thought that as 5GHz is a higher frequency, and it carries more energy, it would be able to pass through walls much more easily compared to a 2.4GHz frequency- similar to how short ...
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Apart from physics, I love music and I want to learn about musical acoustics. I know some things, but the problem is that most of musical acoustics books are written for musicians. That means that ...
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### How to find the constants in Moseley's law?

Recentely we were discussing / learning Moseley's law in class. We have successfully constructed the most basic version of it: $$f=f_R*(Z-1)^2*(1-\frac{1}{n^2})$$ with $n$ being the main quantum ...
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### Angular frequency integral to wavelength integral

I have this integral $$\bar{\omega}^2 = \int\limits_{-\infty}^{\infty}\omega^2|\tilde{F}(j\omega)|^2\frac{d\omega}{2\pi}$$ and I want to convert it to wavelength domain $\lambda$. I know that the ...
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### The Synchrotron at Caltech

In the Feynman Lectures Vol. 1, it says that the Synchrotron at the California Institute of Technology is capable of producing electromagnetic Radiations with a frequency of $10^{24}$ cycles per ...
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### Why is the rotation period finite for nonrotating object?

This question is conceptual in nature as I am obviously failing to grasp something simple here. Say you have a rotating astronomical object (say a pulsar) with rotation period T. The rotation rate is ...
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### Can 2 beams of ultraviolet light intersect and be visible where they intersect?

Is it possible that if you have 2 ultraviolet lasers, that are invisible to the human eye, and if you aim their beams to intersect at some point, that the place of intersection will show a lower ...
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### Frequency of the sound when blowing in a bottle

I'm sure you have tried sometime to make a sound by blowing in an empty bottle. Of course, the tone/frequency of the sound modifies if the bottle changes its shape, volume, etc. I am interested in ...
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### What makes some laser beams visible and other laser beams invisible?

What makes the beam of some lasers: visible? such as the ones used in clubs or such as the laser pointers sold at amazon which if pointed to the sky look like a solid visible beam of light ...
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### How does temperature affect the frequency produced by a fixed vibrating string

How does temperature affect frequency produced by a fixed vibrating string? In the case of the sonometer experiment, the length is fixed so temperature cant really affect length. It affects the ...
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### Interference of two waves of different frequencies relevance to background noise + sonometer

If two sound waves of different frequencies are recorded then does the interference between the two waves of different frequencies alter the resultant frequency recorded. In better context, I'm ...
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### Resonance and natural vibrations in vacuum

In my Physics textbook, it says that if two pendulums of the same natural frequency are placed next to each other and if one is set into vibration, the other starts resonating and when the first one ...
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### Why there are spikes in permittivity Vs. frequency curve?

When the frequency is increased the permittivity of a dielectric material decreases. But in the way of decrease there are some spikes which indicates sudden increase of permittivity for certain ...
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### What is the specific meaning of “Fourier frequency” (as opposed to simply “frequency”)?

I've noticed that many journal articles (in optics) use the phrase "Fourier frequency" to describe, well, the frequency of something. Google scholar search for "Fourier frequency". Example: ...
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### A heavy rope is attached to one end of a lightweight rope [closed]

If one end of a heavy rope is attached to one end of a lightweight rope, a wave can move from the heavy rope into the lighter one. (a) What happens to the speed of the wave? (b) What ...
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### Harmonic oscillator :Two masses are attached to one unfixed spring from both sides (vertically) [closed]

while ($t<0$) the system is still ($\Sigma$ F=0). Mass $m_2$ is held while $t<0$. Mass $m_1$ is located $h_0$ meters above the ground and the spring is currently stretched $L$ meters. The ...
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### What is the Optimal Separation Length for the Tines of a Tuning Fork?

I'm building tuning forks (for fun... why not?), and among one of the design decisions is how far apart should I place the tines (the two long prongs) from each other. I'm not entirely certain whether ...
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### How large or small can frequency in the EM spectrum get?

The largest frequency range is gamma rays, but does the EM spectrum 'stop' somewhere? Like is there a limit to how large a frequency can get? Or how small frequency can get? Is it one of those things ...
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### What really is the significance of the resonant frequency in terms of “ease of vibration”?

I was studying the concept of resonant frequency and I've read quite a few articles and notes on it. What I have understood from what I have read is that the resonance frequency of an object is its ...
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### Audible frequency of an air vent increases with distance: what's going on?

I was just standing near a loud air vent that was roughly at eye level and pointing downward. I noticed something strange about the noise it was making - the further away from the vent I stood, the ...
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### What is the most common photon wavelength in our observable universe (not including the Sun)?

Ignoring the Sun, what is the most common wavelength of a photon that is received by us on average? (I am not asking what is the average wavelength, but rather what is the most common wavelength ...
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### Why am I not hearing frequencies of range 14 kHz-15 kHz? [closed]

Recently, a Radio Station (Red FM, 93.5) started a campaign called "RED FM bajao Machar Bhagao" (English: Play RED FM, scare away mosquitoes). In this, they claim to be broadcasting some frequencies ...
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### What are the proper unit types for the calculation of the frequency of a tuning fork? [closed]

Wikipedia Article on the subject The formula states that the calculation of the frequency with cylindrical tines should be $$1.875^2/(2\pi L^2)\times(Er^2 /(4P))^{1/2}$$ where the variables are ...
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### What's Wrong With This Quantum Analogy?

"Sometimes the idea of the quantum is compared to the units we use for money. A dollar can be divided into smaller units, where the cent is the smallest possible unit." A question I came ...
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### How to compare natural frequencies for different pendulum-spring systems oscilating around the vertical equilibrium?

Im trying to compare the natural frequency of different pendulum oscilation systems around the vertical equilibrium. For the first case the balance of momentum is very simple and the natural ...
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### Why frequency and tension doesn't change in the two medium?

I am reading a book about wave mechanics. There are two different cord (one light and one heavy) connected together, one person waving the lighter one, the wave transverse to the right from the ...
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### Does the Inverse Square Law apply for all frequencies of sound?

We often seem to only hear the lower beats of music far away, whilst the higher frequency sounds seem to diminish more quickly - remaining unheard. I know that sounds with higher frequency have ...
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### Why does medium not affect the frequency of sound?

I read in various places that frequency does not change with medium. Instead, wavelength changes in different mediums due to a change in speed. I understand why speed changes with medium, but I'm not ...
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### Relationship between the frequency and amplitude of wave

I wonder is there any relationship between frequency and amplitude of wave. Generally, most of the people say that frequency and amplitude are independent to each other. But in this case, where it is ...
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### Wave frequencies and barrier width?

I know a fact that says a wave can go through barriers thinner than its length. This is why for example FM radio can be picked anywhere while antenna TV needs direct sight to the transmitter. Is this ...
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### How can a black hole produce sound?

I was reading this article from NASA -- it's NASA -- and literally found myself perplexed. The article describes the discovery that black holes emit a "note" that has physical ramifications on the ...
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### 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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### Gravitational “acceleration” and frequency change of a photon?

For massive particles, force translates into acceleration which again is a change of the velocity vector in direction and/or magnitude. For a photon, the velocity magnitude cannot change, only the ...
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### What's the difference between frequency, spectral and cepstral domains?

I have a hard time teasing apart the conceptual difference between these three domains, and constantly mix them up in my head. I've been reading up on it, but I can't wrap my head around it. a ...
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### Derive frequency given potential using Newton's laws

A mass with mass $m$ has a potential energy function $U(x)$ and I'm wondering how you would find the frequency of small oscillations about equilibrium points using Newton's laws. I started by finding ...
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### What is the frequency associated to the orbitals within an atom?

I was told that there's a vibrational frequency associated to the orbitals within an atoms, but it is a frequency related not to a classical vibration. What Hz frequencies would these be?
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### How are analog clocks synchronized? clocks on the frequency (50 Hz or 60 Hz) connected with power cable to the electricity network

Those clocks that use a motor that runs exactly on the frequency (50 Hz or 60 Hz) and connected with power cable to the electricity network. I mean - a frequency controlled clock / alarm - the ...
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### Is all kind of light same speed?

Is there any speed difference between blue or red light? Is there ever a speed difference? Or does all types of light move at the same speed?
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### Resolution of two frequencies

If I am trying to resolve two features in frequency space, with central frequencies A and B and a 'spread' (standard deviation, FWHM etc.) of $\sigma_A$ and $\sigma_B$ what is the spectral separation ...