1. ### I Good resources for learning a little about the wave vector

Hi, I am looking for a short document discussing the usage of the wave vector. Any recommendations? Thank you!
2. ### I Can the energy in two waves cancel out? If so, why?

I know the answer would be yes, but why? In class, I learned that energy is scalar and cannot be negative (at least in undergraduate class). Thus adding two sources of energy should result in a higher level of energy in general. But here for wave, if we have 2 waves that do destructive...
3. ### I Connecting wave equation with a non-constant force only in bounds

Hi hi, I'm confused about how to mix this two concepts, actually the wave equation: ##\frac {\partial^2 u} {\partial t^2} = v_x^2 \frac {\partial^2 u} {\partial x^2} + v_y^2\frac {\partial^2 u} {\partial y^2} + force## The equation will apply the rule all over the space, but I have the next...
4. ### B Particles with small Wavelengths passing through huge slits?

I´´m confused. How can a single photon in the lightspectrum with wavelength of a few hundert nanometers go through both slits in the double slit experiment at the same time. I understand the wave- particle duality and the concepts in principle. My confusion is in the context of little wavelength...
5. ### B Conversion of Lux into W/m^2

For a physics project, I'm planning to investigate the relationship between the number of slits in a diffraction grating and the intensity of the central maxima. The light meter which I'm planning to use to measure the intensity gives me a result in LUX. I know the wavelength of the red laser...
6. ### B Reflection of a wave by a rigid boundary

I found this on the internet. Source How does the crest reach the end of the medium? As the other end is fixed there is no way the crest can reach the interface. Isn't it? My book gave an alternative explanation. It stated that as there is no net displacement at the interface, we can use the...
7. ### B Laplace's correction

Laplace pointed out that the variation in pressure happens continuously and quickly. As it happens quickly, there is no time for heat exchange. This makes it adiabatic. But newton believed it to be isothermal. Why isn't it isothermal but adiabatic? Why is there a change in temperature?
8. ### Comp Sci Fourier analysis & determination of Fourier Series

ANY AND ALL HELP IS GREATLY APPRECIATED :smile: I have found old posts for this question however after reading through them several times I am having a hard time knowing where to start. I am happy with the sketch that the function is correctly drawn and is neither odd nor even. It's title is...
9. ### Wave on a piano wire

angular frequency= 50 rad/s= 2*pi*frequency frequency= 7.96 Hz k=2*pi/wavelength k=2*pi/(2*1.6m) = 1.96 velocity=angular frequency/ k velocity=50/ 1.96 = 25.5 m/s For some reason this velocity is wrong
10. ### General solution of the spherical wave equation

Since the spherical wave equation is linear, the general solution is a summation of all normal modes. To find the particular solution for a given value of i, we can try using the method of separation of variables. $$ψ(r,t)=R(r)T(t)ψ(r,t)=R(r)T(t)$$ Plug this separable solution into the...
11. ### Tension of a cello string

wavelength of string= 2*L wavelength of string=2*0.70m= 1.4m velocity of string= frequency * wavelength velocity of string= 220Hz * 1.4m= 308 m/s tension= (308m/s)^2 * 0.00196 kg/m =186N Is the tension correct?
12. ### Waves: Calculate the sound intensity from two speakers

Two similar speakers are connected to a stereo system that emits a signal of frequency 𝑓. However, the signal to speaker B is inverted so that positive voltage becomes negative (but with the same absolute value) and vice versa for negative voltages that become positive. A sound intensity meter...
13. ### Can ultrasonic waves be stopped or mitigated?

Summary: After use of Ultrasonic energy we need to mitigate the propagation of mechanical waves, need a solution to stop propagation or at least mitigate it. Hello Scientists, After use of Ultrasonic energy we need to mitigate the propagation of mechanical waves, need a solution to stop...
14. ### Standing wave node counter

Summary: Make a circuit that counts the number of nodes in a standing wave generator I have a an assignment to complete this Term, the assignment consist in making a machine that would produce standing waves in various frequencies, (for example the typical motor connect to a string with...
15. ### Wanting to understand the linearity of wave equations

dear yall with tranditional wave equation on the gre book it says by the linearity in function f which represents wave. it leads to the principle of superposition. I get an intuition about with a standing wave with cos(x)cos(t) you can break it down to pair of left and right moving waves. i...
16. ### A Can I determine mass & spring k from graph of wave, t, a, & vectors?

Classical problems for hookes law generally give either mass or spring constant. What if I have a graph of a wavelike structure that is oscillating which I can use to measure for example: T (period), t (time), Δx (displacement), v (velocity), a (acceleration) and other variables is this...
17. ### How to solve this sound problem (minimum sampling rate required)

Summary: The problem: If one wants to make a digital record of sound such that no audible information is lost, what is the longest interval, Δt, between samples that could be used? ( it gives a hint that humans can hear sound waves in the frequency range 20 Hz to 20 kHz. It should be a very...
18. ### I How to Determine a Photon's Wavefunction After it Collapses?

Suppose one measures the position of a photon without destroying it. From my understanding, the wavefunction of the photon should collapse, and will return to a more spread out state over time. How would one calculate this, specifically the rate at which the wavefunction spreads out from the center?
19. ### I Gravitational waves and density of matter

From what I have read gravitational waves are caused by the acceleration of massive object causing ripples in space time. What specifically causes this, and how does general relativity predict these. Does it have to be a high density of matter, or a large amount of it. How do these waves affect...
20. ### I Does wave superposition consume time?

In Classical Mechanics, waves produced in linear systems, like EM waves, obey the Superposition Principle in which the wave amplitudes of, say two input waves, “add up” to create one output wave whose varying amplitude is the sum of the two input waves. One example would be Young’s Double Slit...
21. ### Amplitude relation with periodic time

Homework Statement Ql: Which sound wave will have its crests farther apart from each other - a wave with frequency 100 Hz or a wave with frequency 500 Hz? Homework Equations Frequency= 1/ periodic time The Attempt at a Solution I did it like that: I just found the periodic time for each...
22. ### Finding Fresnel coefficients from the interface conditions

Homework Statement We have an incident electric field, and there are two cases: 1) the field is polasised perpendicularly to the incidence plane (TE) 2) polarised in the plane (TM) Here I must be able to correctly apply the limit conditions, to find the Fresnel formulas that give the...
23. ### Police Radar Wave Question

Homework Statement [Answer is V = 25m/s, however, how do I get that answer? Thank you!] A police cruiser sets up a novel radar speed trap, consisting of two transmitting antennas at the edge of a main north-south road. One antenna is 2.0 m [W] of the other. The antennas, essentially point...
24. ### I Clear formula for water penetration by wave frequency

I want a clear formula for clear water (and salty water) penetration by giving only the radio wave frequency . I searched the web , the formulas on the web are so complicated . Are there any simple formula available for that ?
25. ### I Are superpositions of waves with different c still waves?

Hi. As far as I know, superpositions of waves are normally considered to be waves too, even in dispersive media. But how can they still be solutions of a wave equation of the form $$\left(\frac{1}{c^2}\frac{\partial^2}{\partial t^2}-\Delta\right)u=0$$ if ##c## isn't the same for all of them...
26. ### Studying De Broglie-Bohm theory books/material recommendations...

Hi PF, im finishing my bachelor soon and I would really like to do my thesis in De Broglie-Bohm theory. I know its a controversial topic but i refuse to accept the statistical crazyness of qm(i passed qm already). Im not a super good student so I´m asking you for some books on this theory, or...
27. ### Progressive wave

The answer is B but I don't understand how. Surely, the string at point P is moving upwards. This video gave a solution but the part that they have indicated as down is a different part of the string and not P.
28. ### B Phase angle and Phase in Simple harmonic motion

I'm a teacher at a Senior High School in Indonesia. I have two Senior High School physics books (Indonesian book) written about simple harmonic motion formula: y = A sin θ = A sin (ωt + θ0) = A sin 2πφ = A sin 2π (t/T + θ0/2π) phase angle = θ = ωt + θ0 phase of wave = φ = t/T + θ0/2π But I...
29. ### B The Simple Pendulum

Is the simple pendulum considered to be an example of oscillatory motion or periodic motion or both?
30. ### B Why longitudinal waves are waves?

i know it's an absurd question, but why are longitudinal waves called waves although they aren't wave-like?