Medium Definition and 390 Threads

Consider a thin transparent plate surrounded by air. The plate's refractive index is exactly the same as the air's, but it does have a small loss (say of the order of 1%). Let the plate be vertical and normal to our "page" or your computer screen. A laser beam passes through the plate at an...

Today in my electro-magnetics class, we were told that the cut-off frequencies of TE and TM waves on a co-axial cable are different. As far as I understand, it says that if there is an electric field with one frequency projected on it and if we know that the problem can be simplified if we see...

Hello PF, I'm reading a paper for a project. In the paper they derive an equation for the effective refractive index ##n=\sqrt{\epsilon^{e} \mu^{e}}## of two stacked layers ##(n_1^2 = \epsilon_1 \mu_1, a)## and ##(n_2^2 = \epsilon_2 \mu_2, b)## where ##a,b## are the lengths and in my case...

Considering classically a light ray in a medium with lightspeed ##c_1## and entering a medium with lightspeed ##c_2## moving with speed ##v## along let say ##y## in the plane of the interface, is it correct to obtain a very complicated formula, having even 3rd power of trigonometric functions of...

Homework Statement in acid medium the standard reduction potential of NO converted to N2O is 1.59V .its standard potential in alkaline meduim at 298k would be? Homework Equations a)2NO+2H ---> N2O +H20 E=1.59 b)2NO + H2O ---->N2O + 2OH- E=x c)2H2O---->2H+ + 2OH- E=0.826 (calculated...

Homework Statement A spring with K=12N/m and an attached bob oscillates in a viscous medium.Amplitude is 6cm from equilibrium position at 1.5 s and Next amplitude of 5.6 cm occurs at 2.5s. what is its displacement at 3s and 4.5s and t=0s Homework Equations x(t)=Xme^-bt/2m The Attempt at a...

I'm reading Special Relativity by TM Helliwell and in it he describes the second postulate and the fact that moving with respect to air changes the speed of sound, and that because light doesn't need a medium it's speed is constant. I remember my physics teacher saying that light itself(EM...

My question is about why the frequency of light or another EM wave does not change while passing through a medium. We know their Speed decrease and wavelenght change but think about this analogy for ex i am 4 meters high and drop 5 balls in 5 seconds and my friend waits at ground he will receive...

Please see my attachment of a recent observation of light traveling through a medium. There is no source, just my observation The packets of light appear to be visible, distinct , moving at different speeds, and display the various colours for each wavelength. Is this normal / possible in a...

Homework Statement An EM wave from air enters a medium. The electric fields are --> ^ E1 = E01 cos(2πv(z/c-t) x --> ^ E2 =E02cos(k(2z-ct)x in a medium ,where the wave number k and frequency v refer to their value in air.the medium...

I am simulating flow through porous medium with VOF method and species transport. For phase change i have Lee Model, and i have no idea about the evaporation frequency and condensation frequency Second I am using the evaporation frequency as 30. The liquid is n-heptane while for vapour phase i...

If we have a medium (say, glass) with an index of refraction, n=1.33, the speed of light in it will be c/1.33. However, blue light travels slower in glass than does red light. Since c is constant and the speed of light is changing, doesn't that mean that the index of refraction will vary based...

Hi, I would like to raise a question about Role of magnetic field while formation of small to medium scale stars emerging from nebula ?

Could the space (air gap) between two DC charged parallel plates be considered to be a "non-linear" medium with respect to an EMF radiated by a coil contained within that space?

<Moderator's note: Moved from a technical forum and thus no template.> An object with mass 96 kg is given an initial downward velocity −3m/s in a medium that exerts a resistive force with magnitude proportional to the square of the speed. The resistance is 60 N when the velocity is −2m/s. Use...

The velocity of light changes when it passes through a medium of a different refractive index. So let's suppose the light is traveling through a vacuum at a velocity c and then passes through a glass wall. Its velocity decreases while traveling through it but then speeds back up to c after...

Hello , I am thinking to work on a RC aircraft ( Airplane ) that can load a small supply of Medical Firstaid in small range. So I need to make it fast and stable. So I'm thinking to use a small Turbo-jet engine in it which will be home-made. Please suggest me -- (1) Is that makes any sense ...

Homework Statement In the laboratory how is MnSO4 oxidised to MnO4- in an acidic medium? a. NO3- b. O2 c. Cr2O72- d. S2O82- (NB: If I've posted this question in a wrong thread please tell me exactly the right place to post it rather than just deleting it and saying to post it in the right...

Homework Statement In a homogeneous, non-magnetic, highly insulating and viscous medium, a moving particle experiences a viscous drag given by the law f→=−bv→. Here b is a positive constant. A particle having charge q is projected with an unknown velocity from a point in the medium. It almost...

I am studying phase and group velocity in non-dispersive and dispersive media. My question is the following: Is there any reason why a dispersive medium simply cannot be modeled as a type of field?

Hi, I am looking for some information regarding maximum current density in conducting mediums, such as a conducting fluid. Say that we have a setup like the figure that I have attached. We are looking down on a conducting medium with a uniform magnetic field coming out of the page and the...

When light travels through a transparent medium and is absorbed then re-emitted, do the phonons just move to a higher energy state after absorption? Is it the same as absorption and re-emission of light by electrons, aside from having a continuous range of available energies?

Hi, i am looking for a general form of a wave equation in a medium. i am not looking for a concrete physical equation but rather a generalized form (preferably in n dimension) of such under the simplest assumptions (it's of course a little equivocal what 'simplest' means but, well). so for a...

It is said that light needs no medium. But light is just an excitation of the electromagnetic field in QFT. This excitation presumably propagates within that field at the speed c and once that excitation has left a point in space, the field has settled down to 0 energy again, analogous to pond...

I just saw this news article on the home page of the university I'm working in: http://www.aalto.fi/en/current/news/2017-06-30/ It seems to be about a study that can potentially explain the redshift of distant stars with a mechanism that's related to the interaction of photons with the...

Looking for the heat capacity of ideal gas due to rotational degrees of freedom. If the temperature of the gas is much higher than the temperature corresponding to the energy differential between states,the partition function can be written as the integral over the density of states. If the...

Homework Statement Homework Equations γ=α+(1/2L)ln(1/Γ1Γ2) where gamma is gain, alpha is absorption constant, and Γ are reflection coefficients. The Attempt at a Solution I'm a little stuck on how to start. If there was no semiconductor gain medium in the cavity then I could just use the...

Homework Statement Homework Equations Brewster's angle The Attempt at a Solution I understand why A is true, but I have no idea what concepts are at play with B, C, and D. Any suggestions?

Hi! Dealing about wave propagation in a medium and dispersion, wavenumber k can be considered as a function of \omega (as done in Optics) or vice-versa (as maybe done more often in Quantum Mechanics). In the first case, k (\omega) \simeq k(\omega_0) + (\omega - \omega_0) \displaystyle \left...

Hi all! I have an optical system made up like this: Circular led source -> smaller circular diaphragm -> circular even smaller lens -> cmos sensor at the posterior focal plane This is the in scale model: The image is optically after the focal plane, but practically it will lie on it due to...

Homework Statement A 300 MHz plane wave propagating through a non-conducting medium having relative permeability= 1, relative permittivity= 78.What is the velocity of light in this medium? Homework EquationsThe Attempt at a Solution n=√(78) v=c/n =3*108/√78[/B]

I understand that the interstellar medium (ISM) consists mostly of neutral hydrogen gas, plus a smaller fraction of helium gas. Furthermore, I gather that between 0.1 and 1.0 atoms per cm3 correspond to the average density values pertaining in our "Local Bubble". The above, however, refers...

can light collectively or individual photons act as a medium for propagation of sound waves?

I was thaught you can create a sinusoidal wave by making a source oscillate with simple harmonic motion in a medium, such as moving one end of a rope up and down to create a periodic transverse wave. For transverse waves, it is easy to see that every particle in the rope moves up and down with...

Hi I was told by physics lecturer that both the wave speed and wave length of light changes when it enters a medium, however I questioned this stating that if both wave speed and wave length changed then frequency must also according to the formula c = fλ. He stated that "frequency is energy...

Hi, I'm trying to evaluate the derivates of first, second and third order of the phase change parameter in a dispersive medium. In such medium the refractive index is a function of the wavelength. In my case it depends on the wavelength in vacuum. \begin{equation*} n(\lambda_0 )\end{equation*}...

Homework Statement A medium has a refractive index, ##n(y)=n_0 \sqrt{1+y/a}## which increases along y. Assume ##n_0## and ##a## are constants and always positive. If a light beam enters horizontally along y, through (0,0), find the curve the path of the light ray takes. Homework Equations ##F...

As I understand it light is refracted when entering a different medium (like from air to glass to air) because it moves slower through the glass, so it will go through the glass in as least time possible , so it bends toward the normal so it can traverse the glass quickly (if that's right word...

Here is the picture of my apparatus.

For this question, I don't want to explore what "space" is (quantum chaos or otherwise), or whether it has mass, etc. Instead, I just want to explore if it qualifies as a medium, like air or water. I have a line of reasoning I want to explore, but as it is based on "space" being considered a...

Dear all, This is my first post and I'm not sure if it's the right place to ask so don't hesitate to advise if necessary. I would like to know if it's possible that an optical detector (the complete system including sensor and front-end electronics) has a better sensitivity at medium flux than...

Why does sound always move at the local speed of sound in a medium (in other words, why is there a set speed of sound for certain medium)? I understand that sound is a compression wave, but shouldn't a louder sound (i.e. one with a higher amplitude) move faster? What about a higher pitch noise...

https://www.inverse.com/article/24863-dark-matter-might-be-smoother-than-we-thought Scientists have yet to actually observe dark matter in the flesh, but most research up to now posits it’s the kind of stuff that clumps up and aggregates into unwieldy masses around the universe. New research...

Currently, I'm doing the CREST award for physics, and my topic is about different methods of finding out the refractive index of a medium. I have already tested out few ways, and now i am thinking about a method where a formula n=c/v will be used(n-refractive index, c-speed of light in vacuum...

Homework Statement A dielectric sphere with the electric and magnetic susceptibilities ε1 and µ1 is rotating with angular frequency ω in a constant electric field E~ in a medium, characterized by the parameters ε2 and µ2. The angle between the rotation axis and the direction of E~ is α. Find...

Really odd question for you guys but I'm curious about your input, and apologies if it's a foolish question to ask anyway(I'm a CS student and this came up in a discussion with a classmate of mine). So I know this is a fairly odd thought and not likely practical in any real world scenario, but...

Waves on water require water to move, sound waves require a medium of the like. My question is what do light waves move in. Empty space contains not much more then low density hydrogen, what medium could light possibly be moving in.

First of all I will being with I'm not an electric engineer so I might be out of my wits, but I will give it a try. So I have an instrument which reads relative permittivity using a transmitter and two receiver placed at different distances. The instrument is calibrated to read either in a...

So my question is, is there a relationship between the density of a medium you are traveling through and the maximum speed achieved for an object of constant mass and shape traveling with constant thrust in both mediums? for example if i knew that an object traveled 8 times faster in 1 medium...

It is clear that gravity propagates at the speed of light in the vacuum. But what happens to gravitational waves as they propagate through material mediums? Presumably they get slowed down but, is it known precisely how much and by which factors, density of the medium or any other properties...