Questions tagged [frequency]
Frequency is the rate of repetitive aspect in the amplitude over a given dimension.
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Changing frequency of light without changing its energy
Three observations were detected in the photo-electric effect:
The kinetic energy of the ejected electrons doesn't change if you change the intensity of light (instead more electrons are ejected with ...
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Frequency of the photon in general relativity
There is an observer at ($r,\theta, \phi$) outside of the Schwarzschild blackhole. A beacon is falling into the black hole along $r$ coordinates of the metric and is emitting radiation. At $r_{em}$, ...
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Why do directional microphones have a high bass response at short distances?
In the audio field, it is taken as a given that directional microphones have a higher response at lower frequencies when the source is close to the microphone. Many directional microphones have a ...
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The light behavior from vacuum to glass [duplicate]
What does the statement labelled mean? This is in Feynman's lectures on physics. Why should the frequency in both vacuum and glass be same?
What is the meaning, that charge sitting on the boundary ...
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Does colour of light depend on intensity of light? [closed]
By intensity I mean frequency of light
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Physical Significance of Frequency of matter waves
So, in our book there was an additional exercise part and this question baffles me:-
Q. Answer the following questions:-
The energy and momentum of an electron are related to the frequency and ...
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What determines the particular frequency of infrared any given object emits?
Infrared (IR) includes EM waves between 780nm and 1mm in wavelength. (Source) As an object gets hotter, it emits a greater amplitude of infrared. What determines the particular frequency(s) of IR an ...
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Frequency dependence of Schwinger limit
Schwinger estimated a field of $10^{18}$ volts per meter as a point of "vacuum breakdown", over which spontaneous generation of positron-electron pairs becomes energetically favourable.
But ...
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Question regarding beats
If two waves of different frequencies, say $x_1=A\sin(\omega_1t)$ and $x_2=A\sin(\omega_2t)$, are moving along in the same direction and these waves satisfy the condition $$|\omega_1-\omega_2|\ll \...
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Why does audio signal amplitude always fall off at higher frequencies?
In the frequency spectrum of every real audio sample that I've ever seen, the amplitude of the frequency components is always higher at low frequencies, then rapidly falls off at higher frequencies.
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What is the beat frequency if two strings with differing tension?
In certain ranges of a piano keyboard, more
than one string is tuned to the same note to
provide greater intensity. For example, the
note at 147 Hz has two strings at this pitch.
If one string slips ...
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Time response of a double-sided frequency response
I am trying to learn more about fourier transforms and inverse fourier transform. For the example below, I am unable to understand the time response signal.
Here is what I am doing,
Step 1: I am ...
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Confusion about standing wave
I learned that the frequency of standing wave of string with fixed ends is $n v/2L$. However, let's think about a small particle of the string. How does that particle 'know' how long the string is and ...
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Frequency of harmonic oscillator potential
Consider, a particle is moving in a harmonic oscillator potential :
$V=\frac{1}{2}m\omega^2x^2$.
The force on the particle will be :
$F=-m\omega^2x$.
What is the unit of $\omega$ here ? Is it $Hz$ or $...
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Is there laser operating at megahertz?
I have tried to find a laser with working frequency at megahertz by Google but failed. Is there exist one?
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How to determine whether an atomic clock had "ticked at the Moon's natural pace"? (Nature 614, 13-14 (2023))
The recent news article "What time is it on the Moon? Researchers plan to build a lunar clock", Nature 614, 13-14 (2023) claims that
"Clocks on Earth and the Moon naturally tick at ...
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Can radio waves with multiple frequencies have the same power?
I was watching data from a spectrum analyzer that shows the frequency of the wave and its power in dBm. I noticed that all frequencies were operating at the same power; however, I don't understand how ...
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Does the wavelength of a sound change from one medium to another?
In my book, it is written that:
v = fλ in a given medium under conditions of fixed temperature and
humidity.
It is also written that:
one of the more important properties of sound is that its speed ...
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In what respect does the wave pattern of a noise and music differ?
Does the wave pattern of musical sounds contain only harmonics (other than the fundamental frequency) while noise contains random overtones (that are not harmonics)?
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Frequency dependent spring
Consider a harmonic oscillator without damping:
$$m x''+ F_s=0,$$ where $F_s$ is the force induced by the spring (usually $F_s=kx$).
Now, consider that the spring's response for a harmonic excitation, ...
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Simple Harmonic Motion: Relation between angular motion and linear to and from motion
What is angular frequency in simple Harmonic Motion?
If simple harmonic motion is a linear to and fro motion then whose angular frequency are we talking about? A linearly moving body cannot have an ...
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Minimum Observable Offset Frequency in Leeson's Formula
It has been argued in some publications that the age of the universe represents a lower limit on observable frequencies (in their paper, corresponding to a value of $10^{-17}$ Hz). The authors do not ...
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The frequency of a sound wave in air is 128 hz . What will be it's frequency in water? [closed]
This question could be solved in two ways . But I want to know which is the correct way.
It could be be solved by taking the speed of sound which will result in having a wavelength of that sound wave. ...
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How does the length of a double open-ended tube affect its frequency? [closed]
I am attempting to build a trumpet, and need to calculate the lengths of the piping for it. I have attempted to find information on this online, but have been unable to find something that can help me ...
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Interferometry maximum wavelength for a set of baseline lengths
I am trying to understand phase ambiguity resolution for interferometry. Unfortunately, all I have are old power points and not really any notes or textbooks on the subject.
I have found in a power ...
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Does the sign on the exponentials matter in the solution of Dirac's equation?
The general solution of the Dirac equation is a linear combination of plane waves. The Positive Frequency Solutions are of the form
\begin{equation*}
\psi(x) = u(p)e^{-ipx},\quad\text{with}\quad p^2 = ...
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How is it possible that the wavelength of a wave can change but the frequency remains the same? [duplicate]
When let's say a beam of light passes through a transparent glass surface, how is the wave able to maintain the same frequency but the wavelength changes ?
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Why are high frequency signals often described by power (dBm) and not voltage/current amplitude?
Let's consider a lock-in measurement of a resistive device. One may do a DC sweep with an added AC component to get a differential conductance measurement. The AC reference component for a typical low ...
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Can we stop light in a lithium niobate crystal and then recover it later?
Lithium niobate is a peculiar and important crystal, with piezoelectric, optical-electric, and photorefractive qualities giving it many applications due to these properties. It is transparent to ...
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Is the Drapers point inaccurate?
Is the Drapers point faulty since an oven glows visibly red without it actually reaching Drapers point? When the Drapers point blackbody radiation frequency is calculated by Wien's law it results ...
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Resonance and differential equation
I've read that resonance can be modelled by the differential equation:
$$\ddot{x}+\omega^2x=f\cos(\omega_\text{d} t), \quad x(0)=\dot{x}(0)=0$$
However, it's mainly explained in the context of a mass-...
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2 fundamental frequencies observed on a wire?
In an A-Level Physics Practical, we investigated fundamental standing waves on a wire using the setup in the attached diagram. Our signal generator had a scale dial, allowing it to vary between x1, ...
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Refractive index of water
The index of refraction is given by the following formula:
$$
n = \sqrt{\frac{\epsilon \mu}{\epsilon_0 \mu_0}} = \sqrt{\epsilon_r \mu_r},$$
where $\epsilon_r$ is the relative permittivity/dielectric ...
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Acoustic Levitation Calculations
I have recently started studying acoustic levitation and I would like to lift an object that is about 2.5 pounds. Surface area is about 5in x 5in. I am not very knowledgeable on the subject and I have ...
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What parameters descibe a gravitational wave?
What are the parameters of gravitational waves and how does the configuration of the system that creates those waves affect the result?
My current state of missunderstanding is:
Frequency (due to ...
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Why use units of $\rm 1/Hz$ instead of $\rm s$?
The Wikipedia page for Planck's constant frequently includes the constant in units $\text{J/Hz}$ or $\text{J} \times \text{Hz}^{-1}$. Is there a reason these units are used instead of $\text{J} \times ...
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What do we mean by 'resonance frequency' of a system?
Whenever we talk about oscillations, we generally take the term 'resonant frequency' for granted, but I don't understand what this frequency depends on.
For example, if we talk about a freely ...
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A question about metal characteristic frequencies
I just noticed that if we mutliply square of plasma frequency for a metal by the electron scattering time, we get another very nice looking characteristic frequency:
$$\omega_p^2 \tau = \frac{\sigma}{\...
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FFT plot not aligning with lower natural frequencies
I have a cantilever beam with gapped springs on top and bottom and an impulse is given at the free end initially.
I modelled it using finite element method with 30 elements.
The beam then oscillates ...
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Why does high frequency have high energy?
The electromagnetic spectrum's wavelengths all travel at the same speed, $c$. Also, the wavelength $\lambda$ and frequency $\nu$ are related by $c = \lambda \cdot \nu$. Since all moving particles here ...
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Do all objects at the same temperature glow the same color?
Does Kirchhoff's law for heat radiation imply that all objects at the same temperature will glow the same color?
In other words, if a piece of molten iron glows the same color as my body, which ...
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Pound-Rebka Experiment
I am new here and have a question.
Does anyone know if the velocity of the photons changes in the Pound-Rebka experiment?
Do the wavelength and the frequency change simultaneously, so that there is no ...
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Why does the amplitude decrease due to friction in forced vibrations?
Basically, in forced vibrations the frequency of the external force is acquired by the body when both the natural frequency and external frequency is different (won't go into that too because I'll get ...
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What is the oscillation frequency of the observed/measured free induction decay signal in MRI?
I recognize that many articles attempting to describe the basics of MRI under simplify a lot of technical details. I would like to confirm the following understanding about the free induction decay ...
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How much frequency is needed to make a tennis ball levitate, using only sound? [closed]
I am planning to make a device that will catch a tennis ball using sound waves to slow down its motion, and make it levitate. But how strong should the sound waves be? Please tell me if there are ...
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Multiple Pendulums and Resonance
Set up with multiple pendulums suspended from a connecting string. Pendulums 1 and 4 have the same lengths and hence, the same natural frequencies. Others(pendulums 2, 3 and 5) are of varying ...
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Can cyclotron/gyromagnetic resonance occur if the peak of an AC wave corresponds with the resonance frequency?
So basically I'm curious if it's possible for cyclotron resonance to occur with a non-static, AC magnetic field if the frequency of it is equal to the cyclotron resonance frequency at the peak AC ...
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Does higher Hertz mean a higher electric bill?
Suppose my electric utility is meant to provide power at 60 hertz, but instead it provides it at 61 hertz. Would my electric bill be higher? Assume I run the same appliances for the same amount of ...
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What is the name for this type of curve?
I encountered this curve in the notes for a physics experiment:
It was described by the equation
$$
A = \frac{kA_0}{m\sqrt{\left(\omega_0^2 - \omega^2\right)^2+(2\gamma\omega)^2}}
$$
EDIT: I think it ...
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Frequency response of ferrite filter
Why ferrite material only passes low frequency and blocks high frequency. I mean what's going inside this material which is leading to show such frequency characteristics?
