Questions tagged [frequency]

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

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How can I calculate the minimum and maximum frequency in a medium?

I know that Ultrasonic frequencies around 1 MHz cannot travel in air. Why is that? How can I calculate the range of frequencies in a medium?
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Can a Cochlear implant impart superhuman hearing? [closed]

The bandwidth of human hearing determined by empirical data is $20 \; Hz$ to $20 \; kHz$. A cochlear implant stimulates the auditory or acoustic or Cochlear nerve directly so that the hearing can be ...
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Is it possible to vary the mass of an object? [closed]

If it could be varied, then what could be used to cause an effect upon an objects mass? Could the boundary of say, the Higgs Field be stretched and so weakened?
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What is the difference between two plane waves with positive frequency?

Is it possible to interpret the first plane wave $e^{(ikx-iωt)}$ as an electron and the second plane wave $e^{(-ikx-iωt)}$ as a positron? I ask because they both have positive frequency (energy), but ...
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Unexpected frequencies on the Fourier spectrum. Are them due to aliasing from Shannon-Nyquist Theorem?

I have recently performed an experiment in which the light produced by a pulsed Ti-Sa Laser is detected. The detection can be consider in this simply way: the laser is turned on and when the first ...
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Why does water easily absorb THz radiation?

It is stated that water is extremely sensitive to THz radiation, absorbing big amounts of this radiation, this being a reason why skin measurements are safe to do using this range of frequencies (1) (...
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How would velocity of sound, the fundamental frequency and wavelength of sound vary when the temperature of an organ pipe is increased?

Here is my approach to this: neglecting any thermal expansion of the pipe: By the Laplace formula for the speed of sound, $V=\sqrt{\frac{\gamma P}{\rho}}$ where P is the pressure, $\gamma$ is the ...
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What does the variable $n$ mean in the frequency of oscillation of drops?

I am currently working on a project to find how the frequency of oscillation of a water droplet falling through air depends on its surface tension and radius. I came across Lord Rayleigh's formulas: $...
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Why do pianos not produce beats?

Beats occur when two sounds that are close in frequency interfere with each other and produce periodic variation in amplitude - called beats. Piano keys that are next to each other seem to satisfy ...
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Calculating frequency shift due to atomic recoil momentum [closed]

The question: An atom of hydrogen emits a photon of energy $2eV = hf_0$. As a result, the H atom recoils causing the frequency of the photon to be changed to $f$. Write an expression for the change in ...
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How does the intensity modulation of a signal change its output?

What does an intensity modulation value of 15% represent regarding the output intensity of the signal? How does it change it? This is based on the statement: "With the setup described above, ...
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Do humans use the doppler effect to localize sources of sound?

Consider a source of sound such as a person speaking or a party of people which makes a continual drone sound of the the same frequency. If a human shakes their head side-to-side with sufficient ...
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Why do we take two measurements of length in a resonance tube and then use their difference to find the velocity of sound?

We already know that $v_s = f\lambda$ where $v_s$ is the velocity of sound wave. Now as per my teacher, if we use a resonance tube to calculate the speed of sound, we first measure the length say $l_1$...
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Why does Wien's law not work for lower frequencies?

I just found out Wien's law is only a good approximation at high frequencies/small wavelengths but am not sure why. Does anyone mind explaining?
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EM waves/ photons

For an oscillating charge that produces a spherical wave, the energy of the wave at a point $r$ is proportional to its $A^2$, where $A$ is the amplitude (which we can see from the Poynting vector). ...
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Why are traditional telephone lines limited to about 3-4 kHz bandwidth?

According to Wikipedia the frequency range of the plain old telephone service is 300Hz to 3.4kHz. What is the reason for this? Why can't the cables and equipment tolerate higher frequencies? Is it ...
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Electromagnetic Waves frequency

Does Gravity affect the frequency of an electromagnetic wave? If so, does it increases or decreases it? Please explain me. Thank you!
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Why is it bad to model a faraday cage's grid as a rectangular waveguide?

My professor argued that we we shouldn't model a faraday cage's grid as a rectangular waveguide, because it is too long for the wavelength. In a rectangular waveguide the waveguide's z axis (length) ...
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Is the wave velocity of sound waves in a medium constant?

I am giving a few parameters to explain my question: If I consider two waves A and B in a medium under same conditions of density and pressure, and If I suppose that: Wave A has a velocity of 100 ms/s ...
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Pendulum with flexible connecting rod: synchrony in nature

Consider a pendulum with a flexible connecting rod. When initializing the free motion, the bob would be released at a position such that the connecting rod is flexed as shown in the figure. There are ...
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Why does increasing radiation frequency produce narrower collimated beams?

In the context of a THz Gaussian beam $(1)$, it is stated: Terahertz output radiation at higher frequency produced a narrower collimated beam owing to diffraction effects (...) What kind of ...
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Natural frequency mass-spring system on inclined plane [closed]

I have to find $\omega$ for this system using the forces. I have a disc $radius = R, mass = M$ By using $F=ma$, I get $mg\sin\theta - kx = m\ddot{x}$ then $$-g\sin\theta + \frac{kx}{m} + \ddot{x} = 0$...
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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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Why do we hear beats?

I've learnt quite recently that to hear beats the sources must emit sound in almost near frequencies Here is a scenario I have a two tunning forks and together the produce a beats of frequency 2hz But ...
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Frequency of a Sine wave? using Wiki equations

Wiki has an equation for frequency of a sine wave. I substituted into the equation and am not getting an answer in cycles/sec. Does anyone know why? As on Wiki: $f = \frac {v_p} {\lambda}$ $v_p = \...
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Frequency of EM waves

When light travels in air, all the component frequencies of light travels with the same velocity $v_{air} = 1/\sqrt {\epsilon_0\mu_0}$ (where $\epsilon_0$ is independent of frequency. Then we say that ...
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Does $f = (c + v) /$wavelength?

If I'm heading at some given velocity into an electromagnetic wave with some given wavelength. From my POV it would appear as if the wave has sped up towards me and as a consequence the wavelength of ...
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How do optical prisms perform a Fourier-transform

I think I have a lackluster understanding of the time-frequency-uncertainty. I know that $\Delta f \cdot \Delta t \ge \frac{1}{2}$ where $\Delta f$ and $\Delta t$ are the uncertainty in frequency and ...
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Minimum detectable signal of base station in free space

I am studying for tomorrow's exam (Communication Systems, part of Computer Science course), and I've run into this question which involves some radio propagation physics. That's why I decided to post ...
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What does the “true” visible light spectrum look like? [closed]

When I google "visible light spectrum", I get essentially the same image. However, in each of them the "width" of any given color is different. What does the "true" ...
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Why must $\omega^2 = k^2 c^2$?

From The Feynman Lectures: "The next subject we shall discuss is the interference of waves in both space and time. Suppose that we have two waves travelling in space. We know, of course, that we ...
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Measuring the natural frequency of a spring-mass system with the graph

On a graph of a system under a external force y = distance and x = time where the external force start at t = 0, it's easy to find the driving frequency. $$F = \frac{\omega}{2\pi}, \omega = \frac{2\pi}...
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If space is continuous, then frequency and photon energy too? [duplicate]

Photon is the quantum of light, i.e., energy comes in discrete level. But EM energy is a function of frequency ($E=hf$). And if frequency has a continuous spectrum, then energy level is continuous, ...
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Are 'Terahertz-pulse lasers', like, 'Terahertz time-domain spectroscopy' and such, of Terahertz-frequency or trillion-pulses-per-second?

From Phys.org: Light-controlled Higgs modes found in superconductors; potential sensor, computing uses. The mode can be accessed and controlled by laser light flashing on the superconductor at ...
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Different frequencies and the same $n-$revolutions

The frequency $\nu$ it is defined as: $$\nu=\frac1T \tag 1$$ where with $1$ indicate one cycle and $T$ the period, i.e. when a material point completes a complete circle. If I want generalize the $(1)$...
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Time Period of a damped physical oscillator [duplicate]

If I have a stick that is oscillating in air, and due to damping will its period increase or decrease? Damping will reduce its angular velocity as it opposes the motion of the stick, however, won't ...
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How does the light and energy breakdown depend on wave frequency? [duplicate]

How does light and light energy "breakdown" (when light is reflected, some light will be transmited, absorbed, or reflected, just like energy associated with light) depend on wave frequency? ...
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Can the energy of a photon be increased, thereby decreasing its wavelength and increasing its frequency?

I know about Inverse Compton Scattering, but is it theoretically possible to take photons with frequencies so low they cannot be detected, increase their energy and hence make them detectable?
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What happens to a photon when it loses all its energy?

My understanding of Compton Scattering is that when a photon collides with a free electron, it will lose energy to the electron, and this loss of energy translates to an increase in the wavelength/...
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How can we discern so many different simultaneous sounds, when we can only hear one frequency at a time?

As I understand it, the eardrum works like any other kind of speaker in that it has a diaphragm which vibrates to encode incoming motion into something the inner ear translate to sound. It's just a ...
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Why does stopping potential remain same on increasing power of Light Source

My question is that Power, which is energy per unit time P=Nhν/t as the formula suggests, can be increased in two ways, increasing no. of incident photons or increasing frequency. If we increase no. ...
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Why does stopping potential remain same on increasing power of Light Source( photoelectric effect)

My question is that Power, which is energy per unit time $P=\frac{Nhν}{t}$ as the formula suggests, can be increased in two ways, increasing no. of incident photons or increasing frequency. If we ...
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How to derive the response function of $m\ddot x + \gamma \dot x + kx = f$?

In a lecture on fluctuation-dissipation theorem, it is stated that EOM: $m\ddot x + \gamma \dot x + kx = f$ Response function $\chi(\omega) = (-m \omega^2 + i\gamma \omega + > k)^{-1}$ However, I ...
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Is the angular velocity of a wave constant?

For a given wave, how does the angular frequency vary? For example, if the wave starts propagating at $x=0$ with angular frequency $\omega$, then at another point in the $x$ direction, does this ...
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Why two vibrations of different frequencies and amplitudes need to be commensurable when the resultant vibration is formed from their superposition?

I was reading chapter 2 of AP French's Vibrations and Waves. In the section "Superposed Vibrations of Different Frequency, Beats", this paragraph confused me :- "Unless there is some ...
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Does wave frequency affect its velocity?

Consider the following information: Waves - whether they are sound or light or water - are local phenomena, which means how the wave decides to move is determined by its immediate surroundings, not ...
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Why do we generally get reflected and transmitted waves that too having same frequency as the incident one?

In a MIT OCW video lecture, a professor discusses a wave on a string having some density moving towards another string. Both of which are joined but have different densities. He goes on to analyse it,...
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What is the frequency of Gaussian white noise in a Bode plot?

The design of control systems, particularly for SISO systems, is made convenient by tools such as Bode plots and the corresponding Nyquist stability criterion. These concepts allow engineers to design ...
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Is there any way to differentiate UV light from visible or IR light?

I'm working on a small sensor system that responds to only UV light and I wanted to know that is there any way to differentiate between UV light and the rest of the spectrum like using lens if so then ...
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Units of angular frequency in a simple harmonic oscillator [closed]

The equation of a simple harmonic motion can be $x=A \cos(\omega t)$. $\omega$ therefore has units of $radians/sec$. I was solving some problems when I found a statement on my notes $x=\left(1+\...

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