# Questions tagged [frequency]

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

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### Is there a strategy for reconstructing a circuit given the frequency response? [migrated]

So I recently worked with a problem where I was given a bode plot where magnitude of the transfer function (the ratio between the output and input voltage) was plotted against frequency of the system. ...
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### Why doesn't the saturation photoelectric current depend on frequency?

From my understanding, even if the frequency of a photon is above the threshold frequency, it is not necessary that an electron gets ejected as the photon may have been absorbed by a metal atom ...
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### Why does frequent remain constant in refraction? [duplicate]

So at school the told us that: V= f x λ In refraction we were told that direction,speed and wavelength changes when a wave crosses different mediums, and on another occasion that frequency is the ...
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### Would it be possible to extract/filter out two waves of different power but same frequency?

If we can use say Fourier Transform to extract every individual frequency on a signal, can we do the same for power? I was figuring if it would be possible to extract them for further inspection on ...
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### Transverse Vibrations of a Cantilever beam. Why does the % change in nth natural frequency increases with n in this case?

This is the problem in detail I have a cantilever beam. Now I am making it stand upright and adding water for different heights of SUBMERGENCE I am doing this by adding an ADDED MASS term from the ...
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### Converting between $F_{\nu}$ and $F_{\lambda}$ spectral density

In papers, spectral energy distributions are given either in $F_\nu$, $\nu F_\nu$, $F_\lambda$ or $\lambda F_\lambda$. $F_\nu$ has units of Janskys, for example. Is there a clear explanation online I ...
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### Characterizing dispersive mediums with frequency

A dispersive medium is defined as a medium where the phase velocity $v_p(k)$ depends on the SPATIAL frequency of the wave. Since we have a relation between $\omega$ and $k$ can we say a dispersive ...
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### The effect of spring constant $k$ (N/mm) on period, frequency under water (no mass attached with spring) [closed]

springs having different stiffness (N/mm) attached with cylinder of specific diameter in open channel flow (water) fully submerged in water. the direction of the spring and flowing water are inline. ...
1 vote
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### How did Einstein calculate the wavelength of photons?

Einstein's Photoelectric equation states that $$h\nu = h\nu_0 + \frac{1}{2}mv^2$$ which uses frequency. But if he assumed light to be a stream of particles how would he calculate it's frequency? de ...
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### How to derive the equation for capacitive reactance? [closed]

How to derive the equation for capacitive reactance $X_C$? $$X_{C}=1/(2\pi fC)$$ with $f=$ frequency, and $C=$ capacitance.
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### What actually is interval of two notes? [closed]

In my book, it is written that if the two notes have frequency $p$ and $q$ then the interval between them is $p/q$. But while solving a question, I found the answer which is like $q/p$. After surfing ...
1 vote
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### How to calculate the energy of a spring-mass system considering harmonic oscillation of the normal mode? [closed]

For a spring-mass system, we know that the potential and kinetic energy are $$E_p = \frac{1}{2}ku^2 \text{ and } E_k = \frac{1}{2}m\dot{u}^2.$$ where $k$, $m$ and $u$ are the spring constant, mass and ...
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### System where Energy Dissipates but Frequency Increases

Is there any example of an oscillating system where, as energy is dissipated by some external force, the frequency of the system's oscillation increases? One of the questions from 2022's IYPT asked ...
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### Understanding the phrase "Classical mechanics corresponds to the high frequency limit of quantum mechanics"

Recently I have taken an interest in mathematical physics and as my background is mostly in math itself, I have quite a lot of catching up to do regarding my knowledge of physics. One phrase that I ...
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### Photons in communications theory

In engineering communications theory we switch between time and frequency domain interpretations. If a pulse centered at frequency F is shot out of a transmitter, it's limited time duration implies ...
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### Dependence of speed of sound [duplicate]

Why does speed of sound only depend upon elasticity of medium and not on frequency of vibrating particles of the medium?
1 vote
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### If two mechanical waves interfere with each other, what is the frequency of the new wave?

Like in the title, if two mechanical waves interfere, for example sound waves with different frequencies, what is the frequency of the new wave? I know that for the beats, the frequency of the new ...
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### Nodes in the air column are not always acting as nodes?

There are many representations of a standing wave column in lets say open-open instrument like flute. In this case one node centrally, and 2 anti-nodes at the openings. However, nowhere do they ...
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### Can the wavelength of the standing wave be different from the wavelength of the sound it emits?

I have a question about standing waves on strings. I'll try to explain the best I can, I searched and researched the whole day yesterday but I am confused still: Every frequency has a single, and ...
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1 vote
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### How does reflectance change with wavelength? [duplicate]

Sorry if this is an easy question, I am new to physics and this field. I have a question about reflectance which i believe to be "effectiveness of reflecting radiating energy" My goal is to ...
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### Does resonance still occur at half, a quarter, etc. of the resonant frequency?

Examples of resonance that I have seen are pushing a swing and shattering a glass. I know the swing analogy, that if you push at the right frequency, you can make the swing go higher and higher. My ...
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### Frequency of vibration of a spring

Hi, actually I'm confused about the velocity formula (In blue boundary) why the velocity of that small element taken in that way.
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### What is the wavelength of red light in vacuum?

According to Wikipedia, It has a dominant wavelength of approximately 625–740 nanometres. However, I'm not sure in which medium this wavelength was measured. Was this wavelength measured in a vacuum?...
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### How can the given formula yield a frequency, when it doesn't have a parameter with time units? [closed]

This is the formula for plasma frequency. $$w_{plasma} = \sqrt{\frac{4 \pi n e^2}{m} }$$ How can this formula yield a frequency, when it doesn't have a parameter with time units?
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### Calculating the movement frequency of a metal rode

We have a car with acceleration $a > 0$. On the top of the car theres a metal rode with weight = $M$ and length = $L$, and the rode is balanced at some angel $\theta$ as can be seen here: The ...
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### Is Terahertz SAR imaging of Earth possible?

The Terahertz band is at the Wavelength range of 1 mm to 100 μm, which is very good for synthetic aperture radar aka SAR since the shorter the wavelength the better angular resolution you get. ...
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### A mathematical derivation of $E = hv$? [closed]

Though at its origin, the formula for the energy of a photon $\varepsilon=hv$ is a postulate, is there a way of proving this formula mathematically, with consideration of Newtonian mechanics and the ...
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### Easy question regarding RF and ion traps

I saw this interesting video: https://www.youtube.com/watch?v=d-qTa_7FtAA In this video, from the 8:55 mark to 11:55, this man explains using unique frequencies for each element(?) with a unique m/z ...
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### How do I convert the Amplitude from Power/Amplitude spectral density?

I've started working on PSD for seismic signals. In theory, PSD signal can be expressed in 2 ways. One in $(PSD=g^2/Hz)$ and other in $PSD=((meter/second^2)^2/Hz)$ and also ASD=(√PSD). Here $g$ is the ...
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### How do you Determine the Fastest Vibrational Mode of a Crystal?

I understand that a crystal's vibrational modes are Phonons and have a minimum wavelength that is limited by twice the equilibrium separation between neighbouring atoms. But I don't understand how you ...
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### Frequencies (ticking rates) of the two ${}^{87}\text{Sr}$ clocks in the experiments at the Tokyo Skytree broadcasting tower

In 2019, researches in Japan (M. Takamoto, H. Katori et al.) carried out experiments comparing two transportable ${}^{87}\text{Sr}$ clocks, one ("clock $\mathsf 1$") placed at the ground ...
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### Can we quantify the pitch of a sound that is a mixture of many frequencies?

How is the pitch of a sound defined quantitatively when it is a mixture of many frequencies? For example, the sound emitted by a plucked guitar string, or say, the pitch of somebody's (normal) voice. ...
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### Is this a good use of the convolution?

I would like to replicate the real response of an instrument to some signal. Here's what I have in mind: I generate some ideal signal. I then add Gaussian noise to it to produce a realistic signal s(t)...
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### Fourier Component And Resonance

Wikipedia defined Resonance as the following : Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is ...
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### Is the frequency of photon invariant?

I saw a stackexchange answer that says the energy of photons is dependent on the reference frame. I did some digging and found that this is because the frequency of photons is dependent on the ...
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### Frequency and Wavelength of light in water [duplicate]

It is known that the speed of light is slower in water than in air. Does the frequency remain constant and on exiting the water, has the frequency changed?
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### Group index derivation issue [closed]

How do I derive the expression for the group index $N_g$ as below $$N_g=n-\lambda\frac{dn}{d\lambda}$$ using the Cauchy dispersion relation below? $$n=n_{-2}(hf)^{-2}+n_0+n_2(hf)^2+n_4(hf)^4$$
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### How to account for signal transmission in measurements of beat frequency between separated senders?

An important technique in optics experiments is the determination of the beat frequency (a.k.a. beat note) between (optical, as good as monochromatic, suitably stable) signals of two senders; say, of ...
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### What is the relation between the vibration frequency of iron metal atoms/molecules and temperature?

Suppose there is an iron piece. When heated, how the vibrational frequency of its molecule/atom will increase? Is it related to temperature?
### How to calculate the wavelength of the sound in the tube in terms of $L_1$? [closed]
Suppose that we have a dispersive medium, for which it is established that $$\frac{\omega}{k\sqrt{1+a^2k^2}}=v.$$ That tells us that if $a>1$ then as the frequency of the wave gets higher and ...