# Tag Info

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The phenomenon you describe is called dispersion. I don't know of a really good intuitive way to describe this, so what follows is necessarily a hand waving description. Cavet emptor. The light is associated with an oscillating electric field, and assuming the material has a non-zero susceptibility it will cause the electrons in the material to oscillate as ...

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Wavelength is just reciprocal of frequency so second question does not make sense. Light scattering can be seen as absorption and immediate emission. If you look at it like this emission probabilities increase with wavelength since the number of final states increases with frequency (you can arrange a wave in more ways inside a box if it has a short ...

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Probably not. A fresnel lens isn't just a rippled surface, it has discontinuities, or straight edges. The area of these edges mostly causes loss of incident power. The optics designer wants a good ratio of its (aspheric) area of use to its unused area at edges. Sound and other vibrations could create sine wave-like ripples on the surface of a liquid, but ...

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The outside medium has no effect on visible light once it enters our eyes because our eyes are sealed containers much larger than the wavelength of light that we see. Viewing under water or any other transparent medium doesn't matter at all for the wavelength or frequency.

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Modulation, whether AM, PM, FM or whatever (even CW), necessarily widens the spectrum from that of the pure tone of the carrier. Thus, in the design of any radio demodulator circuit, the bandwidth of the modulated carrier must be taken into account. Generally, the RF signal is down-converted, via a mixer and local oscillator, to an Intermediate Frequency ...

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The frequency of the signal is modulated in a relatively narrow band, and drives the audio circuit in proportion to the resonant power between the signal and a resonating circuit tuned to almost the range where the signal resides. The result is that the power in the audio circuit varies with the frequency of the driving signal Other signals are far from ...

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It's completely possible to change the amplitude (the difference between the maximun value of the wave and the minimun) without changing the frecuency. Think this in AC, where you can have signals with different voltage but the same frecuency. To illustrate it I'll show you this for a harmonic wave: $$x(t)=Acos(\omega t+\phi)$$ You can vary the amplitude ...

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When people talk or sing, most sounds involve vibrations of the vocal folds in the voice box (larynx). Like many musical instruments that produce sound by vibrating, during any one short period of time a Fourier analysis will show some "fundamental" frequency (1st harmonic) which indicates how many times a second the vocal folds vibrate, and also higher ...

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The Nyquist-Shannon sampling theorem is about continuously sampling a waveform. This really matters when a waveform is a mix of many different frequencies. The theorem says you must sample at a rate double the highest frequency. With light you only need to take one "sample" (the energy of the photon or its momentum) to fully know its frequency: \$E = ...

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As I have the same question, and I have a completely different solution, which I would like to share with you. In order to see an invisible wave, the solution is to use another carrier visible wave to interfere or act as a carrier for the invisible wave. The same as the carrier waves used to carry sound waves. The carrier wave, we are speaking about here has ...

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The tension in the two cords is the same because they are tied together. For example if the tension in the thick cord was higher than the thin cord the thick cord would shrink and the thin cord stretch until the tensions were equal again. The frequency has to be the same in both cords because the phase of the wave has to match at the junction between the ...

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