# 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.

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### Does the standing wave equation proof require $\ell=Nλ$?

Consider two identical sources $S_1$ and $S_2$ of waves, separated by a distance $\ell$ (as shown in the figure). The sources produce waves in opposite directions(and towards each other). Now, ...
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### Why is it always $\psi= A \sin kx + B \cos kx$ to solve a wave function?

Why is it always $\psi= A \sin kx + B \cos kx$ to solve a wave function instead of the one with $e^{ikx}$? Both are the solutions but the one with $e^{ikx}$ is seldom used.
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### Why does an antinode form at the open end of an organ pipe?

I recently learnt about reflection of waves in various media and the resultant standing waves formed. In a string which is tied at an end, the wave formed reflects with a phase difference of 180 (at ...
1 vote
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### How do retinal cones see color when the cones pickup photons and not waves?

I am wondering how cones (photoreceptors in the retina) can see color if colors are wavelengths but cones send signals when they absorb photons. Maybe by using the energy level (or only being ...
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### Phase Difference of A Mass-Spring System For Different Starting Points [closed]

I’ve seen a very similar question (almost identical) in a test, but the answer key of the test said that it's quarter of a cycle (90 degrees). I'm a bit confused. Are they the same if you subtract 90 ...
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1 vote
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### Is there a limit for passing of classical waves behind a slit?

For the classical waves is there a limit for them to pass through a slit when the dimentions of the slit are much smaller then the wavelength? I think that the Hyugence principle must be valid and ...
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1 vote
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### Can we tell anything about the velocity at which a spherical stone falls into a lake based on the sound it makes?

Suppose we have a spherical cow... I mean stone, and we throw it to a lake. Can we tell anything about the velocity (speed and angle) at which it falls based on the sound it makes? And based on a ...
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### What, precisely, using mathematics, is meant by "electric field with only an $\hat{x}$ component"?

I am currently studying the textbook Microwave Engineering, fourth edition, by David Pozar. Chapter 1.4 THE WAVE EQUATION AND BASIC PLANE WAVE SOLUTIONS says the following: The Helmholtz Equation In ...
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1 vote
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### Pressure wave speed $v=\sqrt{\frac{B}{\rho}}$ rearranged $\rho v^2=B$ is similar to kinetic energy: $E_k=\frac{1}{2}mv^2$. Is this a coincidence?

The speed of a Pressure wave speed is given by: $v = \sqrt{ \frac{B}{\rho}}$, which seems rearranged very similar to kinetic energy: $\rho v^2 = B$. How can this be understood, is this a coincidence? ...
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### What is the wavelength of light in a practical sense?

Okay, so I know that a wavelength is a distance of crest and a trough added together which makes a whole wave, but what is it in the real sense? Like in the case of sound I know when we say "...
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### Can you explain me the definition of wave number as defined in theoretical physics?

Wavenumber, as used in spectroscopy and most chemistry fields, is defined as the number of wavelengths per unit distance. The corresponding formula is $$k=\frac{1}{\lambda}.$$ However, in theoretical ...
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### Number of Cycles per Second Emitted by an EM wave [closed]

I was doing a test and I found this question I don't understand. Test Question (Question 34) I went to this link to try and figure it out: https://sciencing.com/convert-photons-joules-8508488.html, ...
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### Maximum tensile strain at a point on a standing wave

Objective To find the maximum tensile stress on a wire (of length $l$) at a point $x$ which has a standing wave on it having equation $y=f(x,t); 0 \le x \le l$. My work When the wire is at rest, the ...
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### Do long waves propagate through small openings? [closed]

I have done the following experiment: put some water in glass and covered it with glass cover, then put it in microwave for 10 sec. The water was warmed up (The glass doesnt warm when put in oven ...
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### How to find the magnitude of the maximum transverse acceleration of a given point on a string? [closed]

A thin string 2.50 m in length is stretched with a tension of 90.0 N between two supports. When the string vibrates in its first overtone, a point at an antinode of the standing wave on the string has ...
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### Which procedure could help decide whether a string's total length has a separate effect from the tension?

My AP physics 1 exam is tomorrow. This question is from a practice exam I have but I never really understood the answer Using the setup above, a student tests how the tension in a string affects the ...