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Questions tagged [waves]

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.

Waves are observable physical phenomena that propagate the movement of energy through space and time. Some waves, like sound, require a material medium to propagate energy; disturbing the matter through which the wave passes. Electromagnetic waves/particle-waves require no medium for propagation; they disturb their own respective fields they generate.

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How to determine the direction of a wave propagation?

In the textbook, it said a wave in the form $y(x, t) = A\cos(\omega t + \beta x + \varphi)$ propagates along negative $x$ direction and $y(x, t) = A\cos(\omega t - \beta x + \varphi)$ propagates along positive $x$ direction. This statement looks…
user1285419
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How to "derive" the wave equation without refering to strings?

The wave equation in $3$ dimensions is simply: $$\nabla^2\psi = \dfrac{1}{v^2} \dfrac{\partial^2}{\partial t^2}\psi,$$ and the intuition behind this is that at each point of space with coordinates $(x,y,z)$ we have some quantity oscillating there.…
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Why must traveling waves have the same amplitude to form a standing wave?

I understand the reason for which the wavelengths of the incident and reflected waves must be equal: otherwise, the interference at any fixed position would be constructive at some instants and destructive at others. But why can't two waves of…
Julia Kim
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What is a phase of a wave and a phase difference?

What is the meaning of the phase of a wave and phase difference? How do you visualize it?
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Why do longitudinal waves travel faster than transverse waves?

I have learned that if a medium can transmit longitudinal waves and transverse waves, then the longitudinal wave will travel faster. Why is this the case?
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Why intensity of light(wave) is proportional to the square of its amplitude?

I am confused, Classical wave theory says that Intensity of the light(wave) is the proportional to square of the amplitude. How intensity is proportional to the square of the amplitude?
Gary Grey
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What makes a standing wave a wave?

Well, this is my physics professor's question and it really made me think a lot about standing waves, realising I don't actually understand it. What makes a standing wave a wave? How could I explain it? What actually makes wave a wave?
Divlja Orhideja
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What should be the intuitive explanation of wave equation?

$$\dfrac {\partial^2 y}{{\partial x}^2} = \dfrac{1}{v^2} \dfrac{\partial^2 y}{{\partial t}^2}$$ is the wave equation in one dimension. But what should be the intuition behind it? That is, what meaning does this equation convey? This equation is…
user36790
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What is a wave?

I was watching an outtake of Prof. Brian Cox talking to a tv producer about "gravity waves". Their discussion got a bit side-tracked, because the non-scientist didn't seem to understand what a wave "would look like", and also because there seemed…
DanBeale
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What really is a wave and how it is treated mathematically?

First of all, I know there's a much alike question here but this is not duplicate since I couldn't find there the answer I'm seeking. My problem is the following: I know that intuitively we have a wave when we have some quantitiy (that as I see can…
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Why a ship can't pass through its own wave?

This is a photo of a container vessel. All container vessels are long because they are cruising at high speeds. When a ship is sailing it creates waves. When the wavelength of these waves equal the length of the ship, the resistance that the ship…
veronika
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Apart from the sine wave, are there any other waveshapes that could be thought of as commonly appearing "in nature"?

I'm familiar with the sine wave being something that can be used to model many types of oscillation in nature (and the way that multiple sine waves can be seen as sum to produce complex repeating waveshapes, a la Fourier's theorem). However, I'm…
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A particular solution for the wave equation in 1+1D

I am dealing with the one-dimensional spatial wave equation $$\frac{\partial^2 \phi}{\partial z^2}-\frac{1}{v^2}\frac{\partial^2\phi}{\partial t^2}=0,$$ where $\phi=\phi(z,t)$ is required to solve. According to the algebraic approach on Wikipedia…
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Resultant intensity of two waves

For long I've been thinking about this issue, but ended up with nothing : Suppose you have a point source $S_1$ sending a spherical wave in space of equation $$\phi=\dfrac{A_0}{r}\sin(kr-\omega t)$$ and intensity…
Tofi
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What allows the Wave Disk Generator to be so efficient?

Researchers at Michigan State University recently invented the Wave Disk Generator that is supposed to get 60% fuel efficiency. What allows it to be so much more efficient than a traditional Internal Combustion Engine? I am aware that there is…
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