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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A Formula for the Phase Difference Between the Electric and Magnetic Wave Oscillations?

A) Is there a formula for the phase difference between the electric and magnetic field oscillations, in vacuum, in an electromagnetic wave emitted from an antenna, as a function of the frequency the ...
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44 views

Critical Value for Dispersion of light

If there is a ray of light moving from $n_1$ to $n_2$ you can get dispersion if $n_1$ is a function of wavelength. What angle of incidence ($\theta_1$) will maximise the dispersion? My solution so ...
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19 views

Beam of light from glass to air

I am reviewing some concepts on light and came across a question that puzzled me. A beam of light is incident from a glass into air. The incident ray is 60 degrees to the normal. The question actually ...
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335 views

Momentum of transverse waves on a string

In general, if a wave carries energy density $u$ with velocity $v$, it also carries momentum density $u/v$. I've seen this explicitly shown for electromagnetic waves and (longitudinal) sound waves. ...
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34 views

Wave speed derivation using parabola [on hold]

The derivation below uses a circle approximation of the curve. How would you do the derivation with a parabolic approximation instead?
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96 views
+50

why interference pattern changes with given relation when the source slit changes?

Why for interference condition to be seen the dependence relation should be like $${\frac{s}{S}}<{\frac{\lambda}{d}}$$.Where $s$ is width of source slit and $S$ is the distance between the source ...
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33 views

Can a flow of current be produced in a wire if its is bombarded with Electromagnetic waves?

If you have a conducting wire and you bombarded it with EM waves, is there a frequency (lower then the threshold frequency to liberate the electrons) that would induce a current within the wire. I ...
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72 views

How do light waves get their size?

An atom or (small) molecule has the size of about 100pm. Elektromagnetic waves range from about 0.1nm up to 1 km. The most common way waves (like light) are caused by 'jumping' electrons to another ...
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27 views

Solution of Burgers' equation in preshock region

According to Hamilton's & Blackstock's Nonlinear acoustics (Section 4.5.4) the solution of Burgers' equation of the form: $$ \frac{\partial P}{\partial \sigma} - \frac{1}{\Gamma}\frac{\partial^2 ...
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Mathematical definition of wavefront in case of non harmonic waves

What is the general mathematical definition of wavefront? Wavefront is the surface where, at fixed time, the phase is constant But for non-harmonic waves we cannot talk about phase as the ...
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154 views

Are mechanical energy of an element of a rope and energy density constant in the case of mechanical waves?

I'm confused about energy driven by a wave. Consider a sinousoidal wave moving in a rope. In my view each element $dm$ of the rope follows a simple harmonic motion in time. That means that the ...
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How is the Rayleigh criterion connected to the Abbe limit

I am interrested whether one can derive a formula for the point resolution (like Abbe did) of an optical system from the Rayleigh criterion (without the use of small angle approximation i.e. ...
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248 views

Wave speed derivation for small amplitudes

The above is a derivation for the wave speed equation in my physics textbook. However, I've read online that this equation is only true for waves with small amplitudes. I do not see where this ...
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24 views

Does a reflected evanescent wave grow in amplitude?

When considering an evanescent wave travelling in a region between two regions where the solution takes the form of a travelling wave from the maths we have a forwards travelling wave that decreases ...
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1answer
339 views

Singing: Resonance body open-closed or closed-closed?

Googling yields contradictory results, so here my question: When I sing, my vocal chords vibrate, but my whole body is the resonance body, right? So I would say that when I think about standing waves ...
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93 views

Frequency of an open air column

Given only the length of an organ pipe to be $2.14 m$, is it possible to find what frequency it vibrates at? If I use the equation $f=\frac{v}{\lambda}$, does the $v$ apply to the speed of sound in ...
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75 views

How to derive end-correction value relationship for open-ended air columns?

According to Young and Freedman's Physics textbook, in open-ended air columns like some woodwind instruments, the position of the displacement antinode extends a tiny amount beyond the end of the ...
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61 views

How can I prove that antinodes are present at both open ends of organ pipe mathematically?

I know that for anti node to be formed the magnitude of displacement should be maximum at there. For standing waves in an organ pipe, the boundary conditions are such that anti nodes are formed at ...
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110 views

Pressure standing wave nodes at the end of the open side of a tube

I do not understand why standing sound waves can be formed in a one-side or two-side open tube. Consider a one-side open tube. In particular how does the reflection of the wave at the open end occur? ...
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174 views

Rope waves with a twist

In the picture you see a person walking a slackline. A slackline is a tensioned flatband of polyester. Typical tensions are between 1 kN to 15 kN depending on the length of the line. The lines are ...
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30 views

light and sound speed [closed]

why is the speed of light faster in water than it is in air? And why is the speed of sound slower in liquid than it is in air? Is its difference is related to wave's appearance? like transverse wave ...
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41 views

advantages/disadvantages of a cylindrical microwave oven cavity in comparison to a rectangular cavity

Why are rectangular cavities preferred for standard microwave ovens with a frequency of 2.45 Ghz? What is the reason that you can hardly find a circular cavity? What are the disadvantages of ...
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1answer
38 views

Calculating wavelengths from angles in a diffraction grating? [closed]

I am having some problems calculating wavelengths from some given information about a grating spectrum. A diffraction grating with a spacing of 3μm is used in a spectrometer to investigate the ...
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How much heat can ULF RF waves can generate? [closed]

How much heat can ULF RF waves can generate? Can the heat generated from RF waves burn of insects wings which are in flying state?
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214 views

Why does amplitude of a mechanical wave increase and then decrease with increasing driving frequency?

I was doing an experiment where I explore how the frequency of the oscillation of a vibrating water hose (the end of the water hose), affects the amplitude created by the water path (a wave-like ...
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1answer
43 views

Does amplitude of electric field and magnetic field vary with distance in em waves?

Does the amplitude of electric field and magnetic field of an em wave vary with distance?
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Is it possible for wifi range extenders to deteriorate the quality of the original signal?

I am aware that wifi range extenders work by receiving and then re-transmitting signals, but does this process 'steal' any of the signal that I would usually use?
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32 views

Why do standing waves only occur in some specific conditions?

In the string which has both end fixed then the end point have to be $n (\lambda/2)$ from the beginning point in order to have standing waves. I know it has to start with a node and end with a node, ...
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Are two waves coherent iff they have the same frequency?

The essential property that two waves must own in order to interfere with each other is to be coherent. Two waves are coherent if their phase difference $\phi_2-\phi_1$ does not change in time ...
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388 views

Wave packet in curved spacetime

It is known that the classical equation of motion for a scalar field wave packet on a curved spacetime background gives the geodesic trajectory (the e.o.m. is $(\nabla_\mu \nabla^\mu + m^2) \Phi=0$). ...
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65 views

How I can prove refractive index in an environment is this? [closed]

in "Applied Quantum Mechanics" by A.F.J. Levi, is a problem that I couldn't solve it can any solve it: if electrical filed is: $$ \mathbf{E}\left(\mathbf{r}, \omega \right) ...
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1answer
34 views

Why are phase constants of incident, reflected and transmitted simple waves equal in absolute value?

I was reading Griffiths's book of electrodynamics and i got stuck on the ninth chapter, where he analyses the propagation of a simple wave - fixed form and constant velocity - using travelling pulses ...
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59 views

Effect of motion of medium on frequency

Will the frequency observed by a stationary observer will remain same if only the medium between the source and observer is moving?(ie. both source and observer are at rest and wind is blowing from ...
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43 views

Why does light propagate rectilinearly? [closed]

I found a question: Light propagates rectilinearly because of its: a. Frequency b. Velocity c. Wavelength d. Wave nature. Now the answer given in the reference is wave ...
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189 views

Standing wave on a rope fixed at both sides: minus sign in the reflected wave

I'm studying stationary waves on a rope fixed at both sides. In some books I find that the wave function studied is the sum of incident wave $\xi_1(x,t)$ and of the reflected wave $\xi_2(x,t)$. ...
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2answers
110 views

What is the least count of the timer clocks used in RADAR?

I was checking out some videos in YouTube regarding the working principle of RADAR. To quote some HOW IT WORKS: World War II Radar (720p), part 1, How does RADAR work? | James May Q&A | Head ...
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0answers
17 views

How to convert from overtone to harmonics and vice versa?

I was given this question: If the pipe length in a tube is 1.9 m, at the air temperature inside the tube is 28 °C, determine the fundamental frequency of the note played, fourth harmonic and the ...
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35 views

Can I measure the mode shape frequency of a metal frame with a sound meter

If I 'ping' a metal frame it will resonate in many different mode shapes with different frequencies. I can see those shapes by doing a modal FEA analysis. When I use a sound meter to measure the ...
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1answer
37 views

Subtracting Audio from a Song with Multiple Forms

This question may start oozing into the realm of copyright infringement, but let's discuss the theory first and foremost. I have a song with vocal and orchestral accompaniment from a well-known movie ...
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2answers
43 views

Explanation of ray caustics in E&M

My understanding (now) of a real caustic is that it is envelope of curves or ray-paths that arise due to reflection or refraction from the medium/manifold. My main question is, I am seeing the term ...
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Is speed of sound really constant?

Does not speed of sound actually depend on the frequency and/or amplitude of the waves? If so, why it is constant?
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54 views

Energy in a sound wave possible error?

In a certain text discussing longitudinal waves it stated that for a sound wave, both the kinetic energy and potential energy are maximum at the same time. I always thought that the potential energy ...
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25 views

How does string tension influence the harmonic spectrum?

Hey there fellow physicists & musicians! I have a question both physics and music related. How does the string tension affect the sound spectrum? More precisely, how do the respective ...
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3answers
26 views

When two waves interfere, how to calculate the amplitude of the wave?

As the theory of superposition of waves express the amplitudes of the interfering waves do algebraically sum up. But when we sum up the the total energies of a particle doing a harmonic motion due to ...
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4answers
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Does increasing the tension on a string also increase the density?

Consider a string under tension, for example, a string on a guitar. When a guitar string is plucked, it vibrates at a certain frequency. When the tension on the string is increased by twisting the ...
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Wave speed derivation

The wave speed derivation approximates the wave as a circle. It uses that to know that a=v^2/R. However, numerous functions can approximate the wave. A straight line, x^2, x^3, etc. If I used those I ...
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1answer
27 views

Inertial Waves - Why neglecting the advecting term?

I'm trying to derive the dispersion relation for Inertial waves. In Cartesian coordinates: Inviscid and incompressible fluid is rotating uniformly with Angular Velocity: $\Omega = (0, 0, \Omega)$ ...
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Are all diffusion-like processes described as wave-like in relativity-compatible formulations?

Citing from Wikipedia's article on relativistic heat conduction: For most of the last century, it was recognized that Fourier equation (and its more general Fick's law of diffusion) is in ...