Waves Definition and 1000 Threads

1) How good our approximations of thinking about waves as a function like sin? 2) The power of a sound wave, I have looked on the internet for derivations and all of them used calculus which is a quite expected thing so I skipped it because I still didnt take integration. However I found a proof...

I am totally confused. What is concerning the anisotropy the difference between re-entering gravity waves and re-entering density perturbations and more important for me what is then happening in the photon-baryon plasma between end of inflation and these re-enterings.

Homework Statement Homework EquationsThe Attempt at a Solution For the first part I know the wavelength of light is (1.53 x 414nm) = 633nm But for the second part I'm stumped. Since it's 180 degrees then the waves are in antiphase but I don't understand how to calculate the vertical...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > A transverse wave on a string has an amplitude of 16cm, a wavenumber of 5.7m-1, and a frequency of 39Hz. What is the propagation speed of that wave? (a) 6.84 m/s (b) 39.2 m/s (c) 43 m/s (d) 6.24...

It has been demonstrated that it is possible to make humans hear sounds using waves. Abstract From Journal of Applied Physiology Is there a practical method for shielding? I mean using materials for simple attenuation, and/or altering characteristics of waves (frequency, phase and/or amplitude).

i'm doing an experiment to study the effect of sound waves on fire and smoke and would like to know how can i produce sound waves with frequencies varying from 0-200 hz

Homework Statement Two superimposing waves are represented by equations y1= 2sin 2π(10t – 0.4x) y2= 4sin 2π(20t – 0.8x) Find the ratio of Imax and Imin. Ans is (25:9) Homework EquationsThe Attempt at a Solution I know that intensity is proportional to the square of amplitude and maximum...

There's a long conductor carrying a 60 hz AC current. There's a second conductor parallel to the first current carrying conductor, and a hundred meters away from it. I want to know what the electric potential induced by the changing B field is in the second conductor. Theoretically I could...

https://arxiv.org/pdf/astro-ph/0006077v2.pdf page 5. Tensor Perturbations "Tensor perturbations do not couple strongly to the thermal background and so gravitational waves are only generated by quantum fluctuations, as in standard supercooled inflation". Why? Tensor perturbations are created...

Hi. (I'm sorry for my poor English.) I'm looking for a good book on General Relativity, specially on Black Holes and Graviational Waves. I got Schultz book once ago, but it has a fuzzy notation and does not deal with the math as I suppose to. I know the basics of Differential Geometry, Topology...

I understand that any source of gravitational waves loses energy, which is carried away by the waves. But since the waves are perturbations in spacetime rather than a physical field, they cannot carry energy the way photons do. I have read that this used to be a source of considerable...

Homework Statement Two identical traveling waves, moving in the same direction, are out of phase by π/5.0 rad. What is the amplitude of the resultant wave in terms of the common amplitude ym of the two combining waves? (Give the answer as the ratio of the total amplitude to the common...

I know photons all move at the speed of light and they move in a wave like pattern. So the question is. Do we take into account the up and down motion of the wave when we measure how fast it's moving or do we just measure the forward movement ?? For example, if the wave has higher and lower...

Hi, What is the scientific definition of "synchronous sources" when we talk about the conditions of interference? Thank you.

So i know that magnetic field lines are closed, in an electromagnetc wave how can be these lines closed? i cannot picture this in my head

Homework Statement A long rope with mass m = 10 kg is suspended from the ceiling and hangs vertically. A wave pulse is produced at the lower end of the rope and the pulse travels up the rope. (a) Explain why the speed of the wave pulse change as it moves up the rope; does it increase or...

Hey there. I'm not a expert in quantum mechanics, although have some experience with it, but I'm certainly far from being an expert when it comes to the pilot wave interpretation. For whatever reason, pilot waves have been mentioned quite a lot recently, and so I decided to take a closer look at...

Homework Statement Two speakers A and B are 3.50m apart and each one is emitting a frequency of 444Hz. However because of signal delays, speaker A is 1/4 of a period ahead of B. Find all points relative to the centerline between A and B where there is constructive interference. Include angles...

Homework Statement A radio broadcast antenna is located at the top of a steep tall mountain. The antenna is broadcasting 104.3 FM (in Megahertz) with a power of 5.00 kilowatts. What is the peak intensity of the signal at a receiving antenna located 25.0 km away? Homework Equations Honestly...

Homework Statement ##d=0.52 cm,## ##\lambda=431nm##, ##L=119 m## Homework Equations ##dsin\theta=(m+1/2)\lambda## for constructive/bright fringes since there is a pi shift already The Attempt at a Solution a) $$sin\theta\leq1$$ $$(.0052/431e-9)-0.5=m=12064$$ 2 \e{3} $$ total bright fringes =...

Homework Statement Two waves are produced simultaneously on a string of length L = 1 m. One wave has a wavelength λ of 0.5 m. The other wave has a wavelength λ of 0.2 m. The amplitudes of the waves are the same. At t=0, at what locations x0 is the displacement y(x0) equal to zero? At what...

Homework Statement An oscillator is attached to one end of a horizontal string. The other end passes over a frictionless pulley and is held taught by a mass m. The distance between the oscillator and the pulley is 1.2m. The string has a linear mass density of 1.6g/m and the frequency of the...

If we say electron behaves as wave, does this mean if we were able to see an electron, we would see it moving up and down?

I have read the description of electrons as standing waves based on an analogy with a string vibrating at its natural frequencies: thus the different quantum levels are akin to the tones or harmonics of the string, right? So far, so good, but then I have seen contradictory complementary views...

What properties of waves caused the photoelectric effect to indicate the fact that light was quantized. Why couldn't it be explained by light waves being emitted at the same frequency. I am a little confused about why light couldn't still be a wave. Couldn't the photoelectric effect be explained...

Homework Statement I am given the following figure: These are converging rays that appear to be going to a point F convert to a plane wave upon hitting the boundary between n2 and n1, and I am asked to find the equation for the boundary between n1 and n2 that perfectly accomplishes this...

Hey, guys. We all know power of AC currents is transferred via EM waves, but we seldom use that to calculate power in AC system. The reason for this is wavelength is very long. I want to know if there is really existed a transmission line which is 500km, just the length of EM wavelength, then...

Homework Statement Homework Equations N/A The Attempt at a Solution [/B] Okay, it is not an assignment question. I am just looking for an explanation regarding something I read. Why is the diagonal distance travel time(^-1) equal to (n_2 - n_1){(\frac{1}{c_1} + \frac{1}{c_2})} ?

This has to be a mistake right or just wacko. Not the sprites (which are awesome) but the reference to "gravity waves". I love spaceweather.site but those sure aren't gravity waves? http://spaceweathergallery.com/indiv_upload.php?upload_id=129854&PHPSESSID=pokk9dgvl9o46qaq17rq1jbms6

Hi, just trying to better understand this concept of electromagnetic radiation. My understanding thus far is that it is a traveling disturbance in the electric field. This picture here seems to help me see what is happening...

On the one hand, gravity waves travel at c, but on the other hand, spatial expansion has no speed limit; ie, it can happen at FTL speeds. At first one might think, "So what? Gravity waves are gravity waves and spatial expansion is spatial expansion." But what is a gravity wave other than the...

https://www.ligo.caltech.edu/video/gravitational-waves How do gravitational waves get emitted here? Is it in a sphere or on a flat(?) surface?

Is it possible for two waves traveling at different speeds to be in phase? Why?

Homework Statement So in our report we have to explain why these formulas give the same answer theoretically. We have for an example measured these numbers: Freq.: 16,37 Hz L: 1m m: 0.007 kg T ≈ 1 N λ=1/1=1 Homework Equations v=ƒ*λ=√T/(m/L) The Attempt at a Solution The problem is that I...

Hi all, On the website of gravity waves by PhD comics: At minute 1 and 5 seconds to minute 1 minute 20 secs. "Now if the spacetime between you and me stretched or compressed, we wouldn't notice it if we had made marks on our metaphorical sheet...because these marks would also get...

Homework Statement Refer to the photos, question 21 and 22(the one with a helicopter) Homework Equations Both answers are A The Attempt at a Solution for question 21, if the counts to ten, there are 9 intervals. I divide 20 by 9 and divide it again by 2 and get 1.1s not 0.5s. for question 22...

I have some questions about the first discovery paper that was released about gravitational waves, especially some of the maths. How did they: 1. Calculate the masses of the black holes that merged 2. Calculate the energy radiated away in gravitational waves 3. Calculate how far away the event...

What would happened if the speed of gravitational waves were not equal to the speed of light . Please explain it with example of sun and Earth or any other but in easy way. With reference to general relativity.

You know when you have diffraction gratings, you have to measure the angle between center and first order/maxima right? My question is: can the angle be 90°? Or is it always less than that? d sin θ = nλ Thank you!

Hi all, On the subject of being able to feel gravity waves as a human without machines, I couldn't find a very definitive answer to what I was looking for. First, I reference the video: at 40 tp 55 seconds. Its called: LIGO, journey of a G wave. They say in this clip that when the black...

I know that light are affected by gravity since they have both momentum and energy, but what about other magnetic waves such as radio waves or x-rays or other electromagnetic waves

Hey everybody, Homework Statement : [/B] I came across a question discussing Young's Double Slit interference and was wondering how come when we diffract white light through the slits it gives us a central antinodal fringe that is also white? The question itself came in parts firstly...

Okay, so we learn in basic physics that electric fields are created by charges and that magnetic fields are created by moving charges. After that, we learn that those two are just two faces of the same coin: the electromagnetic field. Also, we know that electromagnetic waves travel trough the...

Hello everyone I couldn't figure it out a simple way to solve 15. 11 C . Please help ! Very appreciated!

Homework Statement Plane harmonic waves of 1/p, 1/q, 1/r and 1/s are travelling, respectively, in the directions of the (non-unit) vectors (1,1,1), (1,-1,-1), (-1,1,-1) and (-1,-1,1). Show that there exists an inertial coordinate system in which they have the same frequency if and only if...

Hi, I have a question about surfing, how fast must a surfer be traveling (paddle velocity) in order to catch a wave? I took the approach to consider the surfer in the wave's frame of reference, then supposed that the surfer would be 'caught' by the wave if the surfer's kinetic energy was less...

Homework Statement A = 20 cm Given the graph, what is the phase constant(in degrees)? (I have already solved for amplitude and frequency) Homework Equations x(t) = A cos (wt + ϕ) The Attempt at a Solution x(t) = A cos (wt + ϕ) Taking from t = 0, we find: 10 = 20cos(w*0 + ϕ) 10 = 20cos(ϕ) 1/2...

My question is about system of infinite number of point like particles with gravitation interaction (classic Newtonian interactions). If the infinite system can be considered to be in equilibrium, uniform density, in 3D, did anyone analyzed this system with regard to propagation of density...

Homework Statement A uniform current sheet in free space is given to be, in phasor form, \vec{J}=\vec{x}J_0e^{-jk_1y} located at the z=0 plane. k_1 < k_0 where k_0 is the wavenumber in free space. a) Describe qualitatively the characteristics of the wave generated by the given current source...

Consider an object of mass 1kg moving with a speed of 1m/s. Theoretically , the de broglie wavelength associated with it is about 3.6x10-37. Now if we calculate the energy associated with this wave it comes out to be 3x1011. This is a huge amount of energy which could be very hazardous but it is...