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Microwave ovens work at a frequency of 2.45 GHz. Their principle of operation is that molecules of fat, or water, absorb this radiation, because they are polar molecules with an electric dipole moment and rotate in response to the stimulus of the electromagnetic field of the microwaves. This absorbed energy is then dispersed throughout the material through ...

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The two beams $l_1$ and $l_2$ are not parallel. The angles they make with the horizontal is: $$\theta_{l_1} = \arctan\left(\frac{s-d/2}{L}\right)$$ $$\theta_{l_2} = \arctan\left(\frac{s+d/2}{L}\right)$$ However the difference between these two angles is so small compared with $\theta$ that it is an excellent approximation to assume they are parallel. If ...

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Light is made up of photons that are really neither waves nor particles. Sometimes they appear to behave as particles (see photo-electric effect), sometimes as waves (see e.g. diffraction). You have either remembered poorly or your teacher has taught you badly: electromagnetic radiation (photons) doesn't require a medium and does not behave as a particle ...

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Is this phenomenon (crown shape) studied and described already? Wetzel (1987) describes and tries modeling the splash process, including the crown. (There's a link to the PDF.) A reference to it may be found on p. 208 of Surface Waves and Fluxes, Volume II — Remote Sensing, Editors: Geernaert, G.L., Plant, W.J. (Eds.). (Google might show you the ...

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I've noticed that everyone is pretty bothered at the statement that both the kinetic energy & potential energy are minimum at the top. But though seems to be apparently-contradictory, it is actually true. In fact at the top, the string has zero kinetic energy as well as zero elastic potential energy. So, I'm providing a bit context here: In order to ...

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The grounding of Huygens's principle is essentially the observation that the Green's Function for the Helmholtz Wave Equation is the spherical wave source $$\psi_G(\vec{r})=\frac{e^{i\,k\,r}}{r}$$ Since approximately monotonal sound waves also fulfill the Helmholtz equation, the reasoning below, and thus Huygens's principle, applies exactly to them as ...

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The use of complex numbers is just a mathematical convenience. It makes calculation of derivatives especially easy, it has nice properties when you do Fourier transforms, etc. You're correct that you can do it all using real numbers, so that's not wrong. It's just - in most people's view - more cumbersome. EDIT In light of the back and forth in the ...

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No, I can't, because that formula is nonsense. Furthermore, referring to the first paragraph of you link: Amplitude is not the measure of change over a single period. The maximum height is the amplitude, assuming the wave is a physical displacement wave. But there are many waves that are not: electromagnetic waves, for example. Amplitude may be ...

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Well.. 1) If you were running at the speed of sound, you probably wouldn't be for long. The human body isn't designed to handle those kinds of stresses. 2) Assuming you're listening to the iPod using ear buds (in your ear) You can probably think of the air between the seal on the ear bud and your ear drum as isolated from the air you're running through, ...

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Having never actually used this formally as a constant, I don't know the utility of it, but I can tell from the definition where it comes from. $E=mc^2$ is the energy associated/belonging to a mass, $m$. $E=hf$ tells us the relationship between the energy of a photon associated with an EM wave of frequency $f$. The kilogram-hertz relationship would be the ...

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Air nearest the water is cooler than air farther above the water. As sound travels slower in cool air, if sound waves from warmer air enter the cooler layer they are refracted downward toward the ear of someone in a boat. If the water is calm, its flat surface allows sound waves to travel unobstructed and to reflect from the surface. Instead of ...

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For any charged particle in uniform motion there is an inertial frame in which that particle is at rest, and vice versa. So if the particle shed energy as EM waves due to uniform motion you would have the odd situation that a motionless particle would also have to shed energy as EM waves. Likewise if a motionless particle doesn't create EM waves then neither ...

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There is already a very useful mechanical equivalent called the hydraulic analogy. You'll find lots of related posts already on this site. All analogies have their limits, but the hydraulic analogy is remarkably good. You can even represent components like capacitors, inductors and even semiconductor junctions.

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As you may know, You can equate a damper with a capacitor and a spring with an inductor. You'd need to transfer the energy from your wave somehow to those mechanics in order to use the damper and the spring.

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I have found a good explanation in the net to my question, so I am sharing it just in case somebody else wants an answer too. Note that the question about "why it reaches double the amplitude" remains , as well as a new problem on why does the answer say that the ring has momentum(because its massless): The end of the stationary string, figure (a), is ...

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It is basically a notation to represent a sinusoidal wave (which is travelling in $+ x$ direction ) in the form : $\sin(wt-kx)$. Had the wavefunction been $\sin(wt + kx)$ the wave function would correspond to a wave travelling in a $-x$ direction. So it's only a notation as far; nothing so conceptual about it.

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It seems to be an effect of the interaction between the liquid and the gas surrounding it, though the mechanism is not understood. You can see videos here of droplets falling in slow motion at atmospheric pressure, and low pressure. The crown vanishes completely at low pressure. The authors of the study claim The mechanism by which the gas affects ...

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One difference that might help you is the following. A moving charge certainly has fields that move along with it, so I understand why you might think it would produce waves. But these fields (the electric field, at least) decay as $1/r^2$, just like the field of a static charge. They also "propagate" at the speed of the charge, because they're following it. ...

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The easiest way to obtain this is by considering the formula for the cosine of a sum: $$\mathrm{cos}\left(\alpha +\beta \right)=\mathrm{cos}\alpha \mathrm{cos}\beta -\mathrm{sin}\alpha \mathrm{sin}\beta$$ Substituting $\alpha=kx+\omega t$ and $\beta=\phi$ gives us (along with multiplying by A): A\mathrm{cos}\left(kx+\omega t + \phi\right)=A\mathrm{cos}( ...

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It has to do with the frequency response of the materials in the wall. Different molecules absorb different frequencies (or wavelengths) producing an absorption curve called the materials spectral response. Lots of materials are very absorptive in the frequencies typical in visible light but start to open up (get clearer) in longer wavelengths. Generally the ...

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If you distribute the boxes at various positions and placed them on scales, then over time boxes would one by one get heavier. And eventually you would notice that some boxes got much more heavy than others. There would be regions where the boxes got lots heaver and region where the boxes only got a little bit heavier and regions in between where the boxes ...

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There are no random motions in solids. All motions are highly correlated, you are just adding up a lot of modes at different frequencies, which looks like random motion if you are only looking at a single atom. It's not totally wrong to look at single particles being in random motion, though, since the Fourier transform of a lot of frequencies at arbitrary ...

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Please keep in mind one is talking of electromagnetic waves. Take the analogy of visible light projected from the location of your WIFI transmitter. Light impinging on objects is either absorbed (energy removed from the wavefront) or reflected. There exist shadows, less light behind somebody etc. So in general energy is absorbed from an electromagnetic ...

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I'm not sure whether you include math analysis in "understanding underlying physics", but the point is that the basic wave is the eigenvector solution of the operator considered in the physical system you study. For surface waves in fluids, writting imcompressible + irrotational + boundary condition at interface (i.e. Airy theory of waves ) occurs to ...

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If you use Lumerical or MEEP to do the FDTD calculation, you can simply add a Gaussian source polarized along $x$-direction but propagating along $z$-direction with the given pulse width and $\tau$ and frequency. Alternatively, you can make both $y$ and $z$ components equal to zero for the source. Is this what you want?

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There are two types of energy involved, and the blurring of this distinction is cause of a huge number of misunderstandings. Light comes in discrete packets called photons. The energy of each photon is proportional to the frequency of the light. On top of that, a light beam can have any number of photons in it, and this gives it its overall power. The power ...

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