# Tagged Questions

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

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### Bohr frequency of an expectation value?

Consider a two-state system with a Hamiltonian defined as \begin{bmatrix} E_1 &0 \\ 0 & E_2 \end{bmatrix} Another observable, $A$, is given (in the same basis) by \begin{bmatrix} 0 &a \...
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### Why do you only hear the bass when someone nearby is wearing earphones?

When someone nearby is listening to music through earphones or headphones, usually you can only hear the bass (unless it's really loud where you can hear the singer's voice and the other instruments ...
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### Frequency shift due to acceleration of the source towards the receiver [on hold]

How does acceleration of the source towards the receiver change the frequency shift? If a source of sound is accelerating towards the receiver, what should be the graph of frequency due to Doppler ...
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### Frequency's relationship to Angular velocity? [on hold]

I have an issue regarding the concept of getting the angular velocity. I know that angular velocity relationship to frequency is w=2π*f, however I have a problem where a right circular cylinder with ...
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### Pound-Drever-Hall frequency stabilisation technique

I am having some difficulty understanding the Pound-Drever-Hall frequency stabilisation technique, when locking a laser to a stable cavity. As far as I understand: We emit the laser frequency, f0....
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### Humans Voice Frequency? [closed]

Do all human beings have a different voice frequency like they have different finger prints? as all of us are unique so probably our vocal folds make different vibrations while saying a same word that ...
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### How does cavity resonance produce EM waves? [closed]

My understanding is it acts like a capacitor and inductor in a loop. The capacitor releases stored energy which is absorbed by the inductor through a magnetic field which then returns it to the ...
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### Why does a remote car key work when held to your head/body?

I was trying to unlock my car with a keyfob, but I was out of range. A friend of mine said that I have to hold the transmitter next to my head. It worked, so I tried the following later that day: ...
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### Frequency dependence of electromagnetic reflection

I was surprised to see that the Fresnel equations for reflection depends on refractive index and angle of incidence, but they do not depend on frequency. Why is this case? Are they restricted to ...
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### How to increase the frequency of light

If we want to increase the energy of the emitted photoelectrons (in P.E) then we should increase the energy of the photons which are related to the frequency of the light, so how is the frequency of ...