Waves are disturbances that propagate through space and time. Classically, they travelled through a medium, disturbing the particles but not changing their mean position. Electromagnetic waves/particle-waves need no medium; they are disturbances in their respective fields.

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Motion of string fixed at both ends

I was reading about the Fourier analysis from Waves by Frank S Crawford Jr. But I got trapped at the very beginning; this is the excerpt that troubled me: Motion of string fixed at both ends. ...
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28 views

Diffraction grating interference question

When deriving the equation for diffraction grating, I was told that all the dotted arrows interfere with each other, and given that assumption, the rest of derivation was fine. But why do they all ...
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143 views

Why we don't use gamma rays, x-rays or ultraviolet to transmit data?

The greater the frequency range of a transmission medium, the greater the number of bits per second it can transmit. In other words, the bigger the bandwidth in hertz available, the bigger the ...
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82 views

Is velocity of de broglie wave faster than light? [duplicate]

In one of the properties of matter waves is that it can travel faster than light. In my test I was asked to prove this. There are derivations of both can travel faster then $c$ cannot faster than ...
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18 views

Anti-glare question

I've got two questions on anti-glaze coating. This is how I understand it: the phase difference between the light reflected by the front surface and the back surface of the coating is pi/2 so they ...
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54 views

Defining charateristic of light wave?

"Light is refracted when it travels from one medium to another." Does the sentence show that light is a wave?
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251 views

Will high amplitude, low frequency light be capable of wrapping around a macroscopic object? [duplicate]

To me, as a macroscopic observer of light, it appears that light moves in straight lines. If I shine a light at object A and object B moves between me and object A, the light hits, i.e. gets blocked ...
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Why don't choir voices destructively interfere so that we can't hear them?

Sound is propagated by waves. Waves can interfere. Suppose there are two tenors standing next to each other and each singing a continuous middle-C. Will it be the case that some people in the ...
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45 views

does the Fresnel approximation apply in the far field?

Most sources I've looked at treat far field diffraction and near field diffraction as separate cases, with the former using the Fraunhofer approximation and the latter the Fresnel approximation. In ...
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48 views

How can a string vibrating in a plane radiate sound?

If a plucked guitar string vibrates in a plane, how are waves produced that travel in all directions? I'd have thought that a vibrating string can only produce waves in its plane of motion.
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Is there one all encompassing electromagnetic field? Or are electromagnetic fields separate and individually generated?

Many people have been using very confusing and sometimes contradictory language when describing electromagnetic fields and electromagnetic radiation. It's going to be hard to word this question so ...
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58 views

Speed of waves in a spring

I recently bought a small Slinky spring so as to observe the speed of a wave along its length. I stretched it out quite tightly in a HORIZONTAL position on a spring holder and then plucked at it on ...
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How to measure stationary waves wavelength at lab?

When conducting the stationary waves experiment, we were to measure the wavelength. Some of us did it by measuring three consecutive nodes, others by measuring the distance from 2 nodes and mutiplying ...
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Why the electromagnetic waves propagate and do not stand still?

I know that the electromagnetic waves are alternating electric and magnetic fields. But I don't get why they can't stand still and alternate at the same point. I would like a logical and verbal ...
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38 views

What mechanism can we use to convert waves energy?

In term of renewable energy, can we use waves as another energy that can be stored and used instead of solar, wind and etc ? What I mean here is not sea waves but another kind of waves such as radio ...
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26 views

Waves, matter displacement [closed]

When a wave travels through matter, the matter's particles return to their equilibrium position once the wave is passed, is that statement correct?
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2k views

Why are ultrasounds used for producing images of body organs?

Low frequency waves can penetrate better than high frequency waves, then why are high frequency waves used in ultrasounds for sharper images? Similar is the case in detection of flaws in metal ...
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102 views

How to interpret the complex index of refraction?

The index of refraction which represents how much light gets refracted when entering a medium is defined as $$n = \frac{c}{v}$$ I have seen it stated in several places, such as here, that we can ...
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How efficient is the forward transfer of energy in gravity (surface) waves?

Ocean waves (properly categorized as gravity waves since gravity provides the restoring force within the medium they travel) propagate the major part of the energy derived from winds along the ...
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32 views

what is the effect on the fringe separation of a single slit diffraction when the wavelength is larger than the slit width? [closed]

i know that the diffraction pattern observed is stronger when the slit width is equal to the wavelength of the wave passing through, but what will happen if the slit still got narrower and became ...
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62 views

What role does wavelength play in the identity of a photon? [duplicate]

According to this question: What determines color -- wavelength or frequency? It is the energy, and thus the frequency of a photon $E=hf$, that determines where it lies in the electromagnetic ...
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reproducing double-slit experiment with sunlight

Is it possible to reproduce Double-slit experiment at home with sunlight probably in a larger scale? Thanks for all the answers (and special thanks to Chris for the effort),so i understand that it ...
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33 views

What are diferent reflection percentages of different colors?

I don't need any accurate answer. Suppose reflection percentage for white is 100% (which is not even true for mirrors) then what will it be like for different colours like violet, green and red etc of ...
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3answers
95 views

Physical interpretation of source term in wave equations

Let me start with an example. If we base our calculations on the Newton's second law without any further mathematical treatment, then our equation describes equilibrium of forces, i.e. it is of the ...
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What are some of the empirical proofs of electromagnetic polarization? [closed]

I am aware of how polarization follows from Maxwell's equations, and how it is possible in transverse waves in general. I also know that Huygens, in his great Treatise on Light, first discovered and ...
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18 views

Forces associated with acoustic levitation

I recently learned about acoustic levitation, and I am interested in creating such a device using two loudspeakers. In my attempts to do the math, the following problem arose - assume I have a ...
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16 views

Can waves change their roll axis?

If I roll a laser emitter 90 degrees on its roll axis, will the "up" and "down" motion of the laser-light wave also roll with orientation to the emitter so that to me it is now osculating "side" to ...
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50 views

Overtones of Bells Over A Distance

The hourly bell tower sound at Indiana University Bloomington sounds like a higher frequency when heard from ~1.4 km away, compared to standing right next to it. Is this effect likely due to the ...
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64 views

Linear KDV eq. asymptotics

The question arises from the book Solitons by P. G. Drazin about the linearized KDV eq. $$ u_t+u_{xxx}=0 $$ My first step was to take a Fourier transform of the equation, find that the dispersion ...
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44 views

Demonstration for the existence of longitudinal electrostatic oscillations

How could I demonstrate that in a linear, homogeneous and isotropic medium without losses but electrically charged, Maxwell's equation admit as solutions longitudinal electromagnetic waves, beyond ...
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50 views

Determining the phase delay between H and E fields

I want to determine the phase delay between H and E fields in a medium with losses and not electrically charged. In this medium we also have $\sigma_c\approx \varepsilon \omega$. The enunciation of ...
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64 views

Einstein's 1905 “Concerning an Heuristic…emission and transformation of light”

I'm currently attempting to read Einstein's annus mirabilis papers, starting with his introduction of the quantization of light in the paper: "Concerning an Heuristic Points of View Toward the ...
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Diffraction of light

If $l_1$ and $l_2$ are parallel how can they both can hit same spot? Why their difference in path length is $l_2 - l_1 = d \sin \theta$ instead of 0?
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30 views

Power and frequency of photons and its relationship with biological safety

I understand that x-rays are more dangerous than radio waves because they are of higher energy, since they have higher frequency. However, it’s less dangerous to stand near a radio station with a ...
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57 views

Can one make a propagating field along a waveguide only have longitudinal/transverse components?

We know that in free space, a propagating electromagnetic wave is always transverse. However, along a dielectric waveguide, the propagating wave can have longitudinal components. The exist of the ...
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67 views

Finding the range of frequencies to which a receiver should be set

I'm working on a study guide for a test for my Modern Physics class, and ran across a question I'm having trouble with. A radar transmitter emits a pulse of EM radiation with ...
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78 views

Intensity of sound vs Speed of sound

I am finding out the relationship between intensity of sound and speed of sound. To do that, I am using this equation: $$I =\frac{∆P^2_{\rm max}}{2ρv}$$ where ∆P max = Pressure amplitude, I = ...
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35 views

How does energy travel past the first node established in a standing wave

wanted to ask as mentioned above that how can energy transfer from the first node established in a standing wave by the superposition of two equal and oppositely directed waves,that is when the waves ...
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19 views

Measure amplitude of a sound wave

I am trying to find out the amplitude of a sound wave. What equation or apparatus can I use to achieve this?
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31 views

The relationship between the standing wave energy and its harmonic

My question is this: suppose we create two different standing waves in a string . So, is the energy of the standing wave dependent on the frequency of the wave ?(assume that the amplitude is ...
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52 views

Amplitude equation

I came across this amplitude equation from this website : http://formulas.tutorvista.com/physics/amplitude-formula.html It states that 'amplitude = distance / frequency'. This means that as the ...
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42 views

Proof of reflected and refracted waves being in the same plane as that of the incident wave and its projection on a planar interface

Please give a proof of reflected and refracted waves being in the same plane as that of the incident wave and its projection on an ideal planar interface between two linear, homogeneous, isotropic, ...
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Describing 3-slit interference patterns

I'm typing up some physics notes about wave interference patterns and want to include a graph of the wave produced by a 3-slit experiment: Does anyone know what formula produces this kind of curve? ...
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Amplitude of wave in a medium varying mass density

Suppose you have a stretch string under uniform tension but consists two section of unequal mass density namely section A and B. Section A has higher density, so lower velocity of wave. Now consider ...
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What is the equation of motion for multiple simultaneous pressure waves in a medium? (In the context of stimulated Brillouin scattering)

My overall motivation is to derive the behavior of Brillouin scattering in a birefringent fiber. Brillouin scattering is a nonlinear interaction between light and sound. In classic Brillouin ...
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70 views

Mechanical equivalent to electric circuits

Could one build a mechanical equivalent to electric circuits ? I'm considering mechanical waves (like shock waves) travelling through a medium here. I'm aware that due to the high loss and practical ...
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107 views

Light always particle in vacuum because it has no medium

My physics teacher told me that light in a vacuum is always in the particle form. So what happens if you perform the double slit experiment in vacuum? Will the light spread like a wave or will it have ...
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In a sound wave, is there rarefactions at both ends?

I was reading my book Physics, For scientists and Engineers, Third Edition, by Randall D. Knight, studying the first chapter on waves. This diagram is provided on page 565: The diagram is easy to ...
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438 views

Wave reflection and open end boundary condition intuition

I need to understand one seemingly simple thing in wave mechanics, so any help is much appreciated! When a pulse on a string travels to the right toward an open end(like a massless ring that is free ...
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157 views

How to propagate $E_x (x,t) = \exp(-t^2/\tau^2-i\omega_0 t) \exp(-x^2/w_0^2)$ in finite difference time domain (FDTD) analysis

Finite difference time domain (FDTD) allows to solve differential equations for time evolution. For example, we can analyze ultra-short pulses in free space by solving the Maxwell's equations. The ...