Medium Definition and 390 Threads

Hi everyone, I am looking to improve the transmission of sound from a small 1/2" electro-mechanical transducer through a plastic medium (about 1/4" thick). I understand plastic is not a great medium for this but I do not have the ability to change this. The defacto setup doesn't work too...

Hello all, When light travels in a medium with negligible absorbance, it looks exactly like light in free space but with a different speed relative to that medium given by the refractive index. In free space, the Poynting vector is given by ##\vec{S} = \frac{1}{\mu _{0} } (\vec{E} \times...

I hope putting this in the high energy section is the right section (if not, please let me know which would be more appropriate!) I felt this was appropriate since the work I am doing is high energy astrophysics. So I'm doing some research this summer, and my tasks were to take some data...

I would like to be sure about one case of the use of Doppler effect with sound waves. If the medium (in the case of sound air) is moving, but there is no relative motion between the observer and the source there is no Doppler effect at all. (And the absence of relative motion is...

Dear PF Forum, Thanks for helping me so far. Lately, I've been reading Universe from nothing and quantum fluctuation. Those are very interesting topics. And I'd like to know more about them. And how the energy of the universe is zero. But before I would study them, there are things that...

So I've heard from multiple sources that one explanation for why light slows down whilst traveling through mediums other than a vacuum is that the light "takes every possible path at the same time" through the medium. Below I've drawn my two possible interpretations of what that means. Can...

Hi everybody. I had a discussion on another (engineers') forum about the "lower than c" speed of light inside a transparent material (e.g. glass). The explanation that I gave is that the reduction of the light's speed inside such a material is only "apparent" and not "real". The incident photons...

Water waves with larger wavelengths travel faster. Why water is a dispersive medium?

I have read some article that describe space like a superfluid, etc.., I don't know if it is mainstream, but surely everybody agrees the vacuum is not empty at all. I'd ask you to try to imagine that space is found to be 'the' medium that propagates EM waves: can you explain why this hasn't yet...

When one hears a police siren, music, and a car alarm all at once, how can these multiple types of vibrations be accommodated by the medium? (Let's take the simple case of the diatomic gases in air.) Is it possible for individual molecules to vibrate and propagate multiple sound waves at once...

I'have searched a lot but could not find latent heat for any kind of medium carbon steel for latent heat from solid to liquid and from liquid to gas. Also I want to know the corresponding melting point and boiling point for that know of steel. Any link for a table would be greatly appreciated...

Electromagnetic waves are known to travel a c in a vacuum, but at lower speeds in a material medium. What about gravitational waves? They are also predicted to travel at c in a vacuum, but what about them traveling through material mediums? Do they get slowed down? by which factor? TX

Homework Statement Based on wave attenuation and reflection measurements conducted at 1MHz, it was determined that the intrinsic impedance of a certain medium is , and the skin depth is 2m. Determine: a) The conductivity of the medium b) The wavelength in the medium c) The phase velocity...

Homework Statement A plane electromagnetic wave of frequency 5×1014 Hz and amplitude 103 V/m, traveling in a homogeneous dielectric medium of dielectric constant 1.69, is incident normally at the interface with a second dielectric medium of dielectric constant 2.25. The ratio of the amplitude...

Normally in explaining the aether model of light it is said that all waves need a medium, so just like sound uses air, light uses the aether. To my understanding sound can travel through gas, liquid and solids just fine without air being partially entrained in the materials. Sound does not use...

Is it because that there are less molecules within one unit volume in rarer medium that light is able to travel through it easier?

Homework Statement - A point charge is placed at the origin of the medium. - The relative permittivity of the medium, \varepsilon_r = a / r, a is a constant, r is the radius from origin to any point around the charge. - Objective of this question is to find the expression for voltage.at any...

Homework Statement Hi everyone. I watched a YouTube video earlier today which said that sound waves travel faster in more dense mediums. For example, sound travels faster in water than it does in air. However, on this webpage http://www.physicsclassroom.com/mmedia/waves/ltm.cfm it says that...

if a ray of monochromatic light comes from a denser medium to a rarer medium does the color reaching a viewer in the rarer medium differ from the actual color of light in the denser medium (as wavelength of light is different for both the media)?

From classical electrodynamics textbooks, we know that the Fizeau experiment supports relativistic 4-velocity addition rule. But a recently-published paper says that the photon does not have a 4-velocity. See: "Self-consistent theory for a plane wave in a moving medium and light-momentum...

First allow me to apologize should this thread be in the wrong forum, I am not entirely sure whether Quantum Physics is the right one. I am also unaware of the exact level to which this question belongs, which is why I went for intermediate. Please inform me if this should be changed to...

I'm a psychologist and I'm currently studying physics but, because this is not my field of study, I'm having great difficulties. I am currently studying biological motion and I have to calculate the jerk of my 2D motion data and I don't even know where to start. My data is basically a bunch of...

ZapperZ submitted a new PF Insights post Do Photons Move Slower in a Solid Medium? Continue reading the Original PF Insights Post.

So I believe I understand Maxwell's equation in vacuum pretty well and I feel like I understand them in different medium when I read in a textbook, but when I have to apply it to exercises I get thrown off quite a bit. For example, I cam across a PhD qualifying exam that had split Euclidean...

my question is just that how does the wavelength and frequency of sound wave change when it travels from rarer to a denser medium ....... and whatever is your solution please give a briefer insight into it.. NOTE: i was recently going through a physics olympiad paper and i found from a...

Hello, As we all know, speed of light of different wavelengths (let's say red and blue) in vacuum is same. However, in medium (like glass) it's different and depends on a wavelength and a refractive index. Let's say we send a short pulse of white light incident into a piece of glass (of length...

Homework Statement Write down the relationship between the linear frequency and the wavelength of a light wave when the wave is propagating in a medium of refractive index, n.[/B]Homework Equations wavelength x linear frequency = speed of light speed of light = refractive index x speed of...

Homework Statement 2 media whose refractive indices are 1 and n respectively are separated by a flat interface. An EM plane wave goes from medium 1 to medium 2 with a polarization vector making an angle of 45° with the plane of incidence. Determine the incidence angle for which the reflected...

Dear PF Forum, Sorry I ask this. I should have googled it or doing the experiment myself. :smile: If a cars runs 50 m/s and at that time fires a missile, the speed of the missile is 100 m/s so the total speed of the missile is 150m/s, is this right? And if we sit at the back seat of an airplane...

Homework Statement A pulse of length 28.7 cm is transmitted from a thin rope to a thicker rope. If the thin rope has a linear density μ1 = 0.316 g/m and the thick rope has a linear density μ2 = 1.85 g/m what is the length of the pulse in the thicker rope? Homework Equations...

Imagine a ferromagnetic medium shaped as a cylinder (a ferromagnetic fiber) with a magnetic relative permeability of μr, tilted with an angle a, as shown in the picture. I would like to prove analytically that the sum of the inductances measured along the x-axis (angle is a) and y-axis...

So we all know that the speed of sound increases with greater density of medium. Conversely, the speed of light decreases with greater density of medium. Does there exist such a medium that is so dense that the speed of sound overtakes the speed of light?

Homework Statement I have been given this problem but I don't think I'm doing it right as I have just disregarded n0? Calculate the maximum length of material (nonlinear refractive index n2=2.5×10-19 cm2W-1) that can be traversed if the total accumulated phase difference between the beam...

Hello everyone! Recently my work has been more involved with high energy physics. I have been looking into some things, and I would like help with an understanding of the speed of light. So far, the main ideas I have seen have been thought experiments, with minor (if any) direction to...

Homework Statement A wave travels in a stratified medium whose index of refraction is a function of the coordinate y. Show that the angle ##\theta## between a ray and the y-axis obeys the following law: ## \frac{d\theta}{ds} = \frac{-(dn/dy) sin(\theta)}{n} ## , where the distance s is measured...

I have attached a picture of a circuit. It is a Hi-Pot applying 4800VAC on a transformer. I would like to control the Hi-Pot and multiplexer by using switches while at the same time protecting the multiplexer from having 4800VAC applied across it. I have been researching for a while and I do not...

I'm a little confused as to how to figure out the pressure exerted on a material pressed between two solid "press plates" Let's say we have 2 .5" thick x 12" x 24" hardened steel plates. I have a 1" thick layer of cloth (say 50+ layers) of 8" x 18" (1ft^2). The fabric is placed between the...

In contemplation and research regarding another thread's question about the asymmetry of doppler shift wrt the medium, I find myself trying to imagine two people talking... or perhaps better yet matching pitch. In still air with both people facing each other at ten paces of course they would...

The refrative index law should be sine(i)/sine(r) but in the answer he done the opposite. I included the answer in the bottom of the question.

Homework Statement So in my textbook it says "The speed of the wave depends on properties of the medium, not on the motion of source or observer. An explosion causes pressure variations in the air around it. This "deformation" propagates outward as a sound wave at a speed dependent only on...

Can anybody give me a simple and easy example to understand it

I read somewhere that for a wave traveling in a medium a particle (of medium) "gives"(I am not sure if that is the right word) energy to adjacent particle.Is this correct? And if it is why and how does this transfer take place? Also what role does inertia of particle play in wave propagation?

In the FAQ section 'Do Photons Move Slower in a Solid Medium?', it says that light is slower in a medium when its frequency is beyond the phonon spectrum. So do lights that have frequency within that spectrum move at the speed of c, not being slowed down by the medium?

The speed of light changes according to the medium that its in and I don't understand why. Is it because each particles in the medium has a bit of gravitational forces so that the light doesn't travel in a straight line, or perhaps because of something else?

I'm reading this tutorial and having some difficulty in understanding its derivation. I take as granted that electric energy within a volume \Omega is defined by: W = \int_\Omega \phi \cdot \rho \cdot d^3r where \phi = \phi(\textbf{r}) is the eletric potential, \rho = \rho(\textbf{r}) is the...

Hello, Do you know the total dissolved particle molarity of fibroblast growth media, and could I achieve to keep the osmotic pressure constant while adding both salt and water to it? (I am assuming the salt does not pass through the cell membrane) Thank you.

I'm trying to understand the concepts of physics, but there's one thing I don't fully get... If there is some matter with a spatial and temporal coordinate, let's say coordinate X, is the matter "in" that time and place, or "is" the matter that time and place? In other words, does space-time...

Homework Statement Show that the solution of the form ρ1 = ρ1(x±a0t) satisfy the equation: ∂2ρ1/∂t2 - a02∂2ρ1/∂x2 = 0 and that they correspond to waves propagating in the directions x increasing or decreasing. Homework Equations P = P0 + P1 ρ = ρ0 + ρ1 u = u1 The Attempt at a Solution P1 =...

Hi all, I've read that when light undergoes refraction into a medium with higher refractive index it changes speed and this is explained by the electrons of the medium absorbing the photon energy, they hold onto it then eventually re-emit the light if the frequency of light doesn't match the...

Homework Statement I need to find the green function for a dielectric sphere (\epsilon_1) inside another dielectric medium (\epsilon_2) using the method of images. Homework Equations In gaussian units I have: \phi=\frac{q}{\epsilon|r-r1|} The Attempt at a Solution Due to the symmetry of the...