# Tagged Questions

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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### Finding speed of light by $c=f\lambda$?

When considering EM radiation as waves it is said that it is electric and magnetic fields that oscillate with time. Therefore $f$ is not frequency of distance but of electromagnetic fields. I have ...
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51 views

### Why would a screen(with touch controls) in a vibrating environment be readable if its refresh rate is dynamically matched with vibrations?

So, I was reading about this Dragon V2 and it has got touch controlled screens, but screen might be unreadable for pilots because of engine vibrations and whatnot. I came across this comment on reddit....
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### Need help visualising transverse waves

From studying waves I find that I can visualise longitudinal waves where the wave propagates in the direction of the displacement. However I don't understand what causes the propagation perpendicular ...
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### Do electromagnetic waves always move in straight lines?

When we send an electromagnetic short wave to the sky, it reflects due to the ionosphere effects. But if we send it horizontally, is it correct that it moves around the surface of the earth, and if it ...
3answers
117 views

### Shaking water inside bowl causes waves but why does the water stabilize?

Suppose you shake water inside a container, then at first the waves goes up and down strongly but they gradually dissipate. What makes them dissipate?
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### Does sound cancel itself out?

If there are two 10 x 2 x 1 foot rectangles in space and they are lined up so if they hit each other there will be no spots that are not hit in the front of the rectangle. Then they are pushed forward ...
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### Uncertainty and wave-trains

My textbook and the following extract from feynman's lectures present the same idea regarding wavetrains and uncertainty in their wavelengths. Why is it that a wavetrain confined to some space has an ...
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### Will changing amplitude change the frequency? [closed]

Will changing the amplitude change the frequency of a wave, or is it possible for a specific frequency (50 Hz. for example) to generate from shifting amplitude patterns?
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### Relation between the direction of propogation of sound and loudspeaker's diameter

Sound waves from a conical loudspeaker spread nearly uniformly in all directions if the wavelength of the sound is much larger than the diameter of the loudspeaker. Sound is essentially ...
2answers
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### Moving an object in hand back and forth creates a gravitational wave?

Does moving an object in one's hand back and forth create a wave? It creates a changing gravitation field and that propagates as a wave, right? How does that differ from a "gravitational" wave that ...
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### The image of a wall clock is to be obtained on the opposite wall 2m away by the means of a convex lens. What is the minimum focal length required? [closed]

I'm in 10th grade and this question came in my physics test. Nobody was able to answer this question correctly except my physics teacher who says that the answer is 2m. My answer is that there should ...
1answer
127 views

### How can a probability distribution have wavelength (de Broglie wavelength)?

The wave function described by Schrodinger's equation is interpreted as describing the probability of a particle in at any point in space, i.e. a probability distribution. Since this distribution ...
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### Michelson Morley experiment - why is there an interference pattern in the first place?

In descriptions of the experiment, the two arms of the interferometer have the same length. There's an interference pattern which was expected to be shifted when the system was rotated 90 degrees. But ...
2answers
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### Is this SISO (single input single output) or MIMO (multiple instead of single) system?

If I transform wave equation for vibrating string Mx′′+Cx′+Kx=b(t) in linear system using $x_1(t)=x(t)$ and $x_2(t)=x_1^{'}(t)$ vibrating string equation becomes $Md_tx_2(t)+Cx_2(t)+Kx_1(t)=b(t)$. ...
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### Can sound reflect from itself?

If it is possible, what kind of conditions would be necessary? The case with electromagnetic waves could also be interesting, but I don't think that is possible.
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### What is the distinction between a “ray” and a “wave” in optics?

What is the distinction between a ray and a wave in optics? From what I can gather, the only discernible difference is in nomenclature, where a ray simply refers to an EM wave with short wavelengths. ...
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### Wave on a string to sound wave

If you have a string of 2m in length, and the wave speed on the string is 2m/s. and when then string vibrates at fundamental frequency the wavelength of the wave would then be 4m. However, the sound ...
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80 views

### Question about the wave function of a travelling wave

I have a confusion about the wave function of a travelling wave. Suppose we have a wave function of a travelling wave travelling towards the positive direction of x axis  u(x,t)=A\cos\left(\omega(...
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### The property of transparent lens [closed]

My question is this : what is the property of transparent material that is used for lens?. I think that it allows the light to pass through ( absorption property) and does not bend the light ( ...
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### Why do higher frequency electromagnetic waves bounce of of smaller particles in the atmosphere but the lower ones dont?

I assume they have more energy but what is it more deeper and clearer than that that explains it?
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### What parts of a string stretch most when a wave passes through it?

So there's a (transverse) traveling wave on an (ideal) string under tension. Why does the stretching occur around zero displacement? Why not at the crests?
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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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### Books on waves with Fourier Transforms [duplicate]

There are many waves and oscillations books out there that also include Fourier analysis but very few give the subject a thorough treatment, they just pass it in a few pages. If anybody has any ...
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53 views

### What justifies adding phasors' vertical components

I learned that, when superimposing two waves on top of each other to calculate the resulting wave's amplitude, it's helpful to use phasors. From what I gathered, phasors are vectors originating at the ...
2answers
102 views

### Physical meaning of wavelength of a EM Wave

The wavelength of a wave is defined as the spatial separation after which it repeats its shape. It is easy to visualize it for one dimension but if we consider a light wave/EM wave which is ...
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### Molecular orbital theory

What I have learnt : When two waves overlap in phase, the resultant wave formed had a greater amplitude than that of the two interfering waves. When they overlap out of phase then the resultant ...
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### What is slinky-approximation?

I was reading the derivation of wave-equation from Berkeley Physics - Waves by Frank S. Crawford Jr. Let $\Delta z$ be a small segment of a continuous string . At equilibrium, tension is $T_0$ at ...
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### Zero stress boundary conditions for the acoustic wave function

When is it appropriate to use zero normal stress boundary conditions when solving the acoustic wave equation. That is when the pressure is equal to zero.
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### Why use different arguments to plot a sine wave?

In my Electronics class was given some examples of sine wave graphs that represent voltage in respect to time, $v(t) = Asin(wt)$ and other graphs whose $x$ axis is $wt$ instead of $t$, like in the ...
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### Wave equation - dissipation

The book states that the wave equation assumes no dispersion and no dissipation, with dissipation defined as a loss of energy and thus a diminution of amplitude. How can a spherical wave be described ...
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### Is difference in wave number always small?

Over the last few days I have been looking at a derivation of group velocity. The derivation is the one shown in this question Deriving group velocity. I have seen this derivation in many places, and ...
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6k views

### Why can't transverse waves travel through a liquid?

Can someone explain why a longitude wave can pass through the liquid, but a transverse wave can't. And can someone recommend some good animation of these processes.