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Questions tagged [frequency]

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

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Why is photon quantized in vacuum? [duplicate]

Apparition of quantized energy levels in quantum physics is usually explained in analogy with sound waves in a box (like in music instruments): the wave has to satisfy the boundary conditions and ...
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30 views

3 waves, calculate time of collective period?

I have 3 sinusoidal waves. Frequencies 1.3, 0.8 and 1.5 Hz. They all start at zero amplitude, at the same time. How do I calculate the time it takes for my waves to meet at zero amplitude again, and ...
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How can I get the wave number and wave vector? [on hold]

$$\overrightarrow{E} = (-10 \hat x + 4 \hat z) e^{-j(2x+5z)}$$ I recently started to study electromagnetics, but I'm having a hard time following up. May I ask how to calculate the wave vector $\...
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Temporal period to frequency conversion (optical cavity)

Why is it that the Finesse and resonance width of a cavity calculated in time domain is different from that calculated in frequency domain? Here is a temporal signal that I recorded with a photodiode ...
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Determine frequencies present in complex wave from oscilloscope graph

How can we determine, from an oscilloscope trace of a complex wave like that shown below, the frequencies present? For example, in the case of the wave shown below, we are told that there are exactly ...
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Why doesn't the wave's frequency change as it gets refracted? [duplicate]

I know that frequency means a complete wave produced per second. But when the wave gets refracted, it's wavelength decreases. If the wave's wavelength has decreased doesn't it means that the wave has ...
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36 views

Difference between amplitude modulation and intensity modulation

If a few kHz modulation is imposed on the 80MHz pulse train of a laser by the means of either a Mch-Zehnder interferometer or a single acousto optical modulator triggered by an external function ...
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Does putting a part under stress change its natural frequency?

It is easy to imagine how tension changes the natural frequency of a wire. Intuitively it happens with a guitar string when you bend the neck. However, does putting a beam under stress (internal or ...
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Can you change the wavelength of light keeping frequency constant and can you do the opposite as well? [duplicate]

Can you change the wavelength of light keeping frequency constant and can you do the opposite as well? I understood the basics but please don't hesitate to go deeper into the concept. Also, If you ...
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What does it mean to hear the gravitational waves?

In last few years, I watched a lot of YouTube videos claiming that gravitational waves can be and has been heard. They also play a short audio signal. How do experiments such as LIGO replicate the ...
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If a photon doesn't experience time, how can it have a frequency? [duplicate]

It is said that photons, moving at c, do not experience time. But then, if a photon doesn't experience time, how can it have a frequency?
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Why we use Nyquist frequency limits

Can someone in simple terms why you would use Nyquist frequency limits when processing a signal? What benefit does it provide, and how does it affect the results? And how does it relate to the Nyquist ...
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30 views

Determining the Frequency of a Gong [closed]

I want to build a circular Gong for Sound Healing and I want a specific frequency but I don't know how to calculate it. Does someone can help me?
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28 views

Logarithms in uncertainties

I'm looking at the following plot: The vertical lines show the upper and lower frequency bounds for each of the bands W4, W3, W2...and I'm trying to convert them to wavelengths using $\lambda=\frac{c}...
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How does a wave become a color?

I am a mathematician and not a physicist, so please be gentle to me. The best explanation I found so far about light waves was here: https://youtu.be/7eutept5h0Q If I got it right, then light is a ...
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37 views

Possible to change optical properties of tissue?

I am looking at an optical coherence tomography scheme which is based on a michelson interferometer. The basic idea is that a laser beam is split by a beamsplitter, half of which goes into some tissue ...
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Chladni Plate subjected to different waves

A Chladni plate consists of a flat sheet of metal, usually circular or square, mounted on a central stalk to a sturdy base. When the plate is oscillating in a particular mode of vibration, the nodes ...
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2answers
69 views

The meaning of $\rm mHz$ and $\rm Hz^{1/2}$

If Hertz(Hz) is for once cycle per unit time what does mHz and $\sqrt{\text{Hz}}$ represents? I mean what is the physical manifestation of the a fractional power of a unit ?
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Phase difference in a standing wave?

What would the phase difference between P and Q be? I assumed that because they are 1/4 of a wavelength apart, it would be Pi/2, but supposedly the difference is 0.
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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
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What is frequency entanglement?

If frequency (or energy) is regarded as a quantum property, can one generate a pair of photons with frequency entanglement? What would be the uses of this type of entangelment in say, sensing? How ...
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Relationship between Planck's law and absorbed frequencies

What is the relationship between the frequencies of radiation absorbed by a material and those emitted? I know that Planck's law tells us the spectral radiance, but how does this map to those ...
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Why use ultrasound for medical imaging? [closed]

What advantage does ultrasound have over sound between 20-20000Hz that it is used in medical imaging over sound in that frequency range?
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What is the energy of one photon radiation? (Probably super basic for you)

So, this is given question: The radio station emits radiation power of 6 kW, wavelength 3 m. a) What is the energy of one photon radiation? b) How many photons are emitted in 5s? I tried ...
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Why does $\sqrt{\frac km}$ represent angular velocity and not frequency?

When I break down $\omega = \sqrt{\frac km}$ (angular velocity for a simple harmonic oscillator) into its units, I get: $$\omega = \sqrt{\frac{kg * \frac {m}{s^2}}{kg *m}}$$ which simplifies to: $$\...
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When you increase the tension on a string, how is the standing wave affected?

I know that wave velocity is the product of wavelength and frequency, and that velocity is proportional to string tension. Does this mean that if you increase the tension on a string, the wavelength, ...
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Hypothetical maximum energy of a single photon [duplicate]

I'm no physicist so it might be a stupid question but is there a maximum energy a single photon can have? My idea was, that there might be restriction for the minimum wavelength and I thought about ...
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1answer
54 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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82 views

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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2answers
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Do photons exist at all possible wavelengths? [duplicate]

My question refers to Photon flux spectrum diagrams. The diagram shows the number of photons at different wavelengths. My question is whether the graph is granular or continuous. Do photons exist at ...
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Change in pitch on a flute due to blowing at a different angle

Why is it that the location of where the air hits the inside of a tube, the pitch is affected? When playing the flute, directing the air downwards lowers the pitch. Another student suggested that this ...
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4answers
587 views

Sound waves in different octaves

How do the sound waves compare between different octaves? Why is it that you can play a low c and a c, and they are at different frequencies, but the same tone? An octave above a note is the fourth ...
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1answer
108 views

Why are angular velocity and angular frequency not measured in Hertz?

Recently, I was doing my homework and I found out that Angular Velocity and Angular Frequency can be calculated using $\omega=v/r$. This means the units of angular velocity and angular frequency are (...
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1answer
71 views

What is complex frequency? [closed]

I am learning EE, and about complex frequencies, but what is its physical meaning? What is it used for? Why is it? And only happen in the laplace transform?
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In the SHM equation $F= -kx$, $k =mw^2$ why not use $mf^2$ where $f$ is frequency $w$ here comes out to be $1/s$ not $\text{rad}/s$?

The reason I am stating this is because on calculating the units of w(omega) I found is equal to s^-1 not regular the rad/s. Proof: ...
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Multiple frequencies [closed]

could someone please inform me how it is possible to send multiple frequencies down one wire? I’m referring specifically to a communication protocol known as HART. It seems they send a 4-20mA signal ...
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Is there an equation to relate a glass's frequency to its mass when it's struck with a spoon?

The mass therefore would be changing because I am pouring in water and testing the frequency at different volumes. Obviously as the volume increases the mass increases and the frequency decreases. ...
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Superposition of light waves of different colors

Can someone please assist? My question is regarding visible light. If, for example, red light and blue light are waves of different wavelengths and frequencies then how do they combine with all the ...
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Deciding amplitude for Beats

I have two harmonic sound waves of nearly equal angular frequencies $\omega_1$ and $\omega_2$, and whose equations(which I have particularly modified for convenience), are $$s_1=a.\cos\omega_1 t$$ $$ ...
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Why do we take the derivative of the number of modes with respect to frequency (Rayleigh-Jeans)

Source: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/rayj.html We arrive at this result: $$N(\nu)=\frac{4}{3}\frac{\pi L^3\nu^3}{c^3}.$$ So now we have a function representing the number of ...
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Why does a sonar or radar's frequency correlate with its resolution?

A sonar's (or radar's) frequency determines its limit on the smallest size that it can detect and its resolution. I've heard that it's due to aliasing, if so, please explain the reason behind it a ...
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Why does the frequency of a wave does not change on reflection and on transmission? [duplicate]

I wanted to know why the frequency of a wave does not change even on reflection or transmission and does it only depends on the source only.
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Yi's Bell sound and how it relates to temperature?

Yi's Bell is an ancient chinese musical instrument that plays different sound frequencies when its heated than when its in room temperature. My question is Why does that happen? Why does higher body ...
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1answer
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About sound of non-existent channels on FM

Well, I have learnt about resonant frequency due to series capacitor and inductor, and how the current at resonant frequency is highest, but i am confused about the sound, which appears even when no ...
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1answer
49 views

Energy-frequency dependency of a photon and its medium of propagation

Is the equation relating a photon's energy to its frequency the same regardless of its medium of propagation? And for the equation relating its momentum to wavelength as well?
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55 views

Microwaves in other media

I saw a video on how microwaving grapes make plasma. He said that the refractive index of microwave is about 10 inside the grape. Now, we don't know the wavelength of the microwaves in the grape or ...
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How can I use a frequency counter to show the rpm of a spinning disc?

I don't want to unbalance the disc by attaching anything heavy to it. Is there a way of doing this optically?
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1answer
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Where does the sound we hear from short circuits come from?

Title is self explanatory. Whenever I see or watch a short circuit happening, there is always a humming/buzzing sound going on (e.g., the sounds we hear from this short circuit compilation video). ...
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How can be various frequencies in one place?

How can we receive different radio shows in one place, they are coded in phase or frequency or amplitude of electromagnetic waves, but shouldnt elecreomagnetic waves interact each other, and all ...
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Wavelength of Intermittent Laser vs Prism

The following YouTube video from Sixty Symbols ( What is the maximum Bandwidth? - Sixty Symbols https://www.youtube.com/watch?v=0OOmSyaoAt0 )states that only a laser which always shines truly shines ...