Medium Definition and 390 Threads

Why does the phase of the reflected wave from a denser medium change?

What is the difference between space and vacuum? Since light waves require a medium to travel, then what is the medium in space?

Hello, Please see the attached sketch. A car hits a mass of soil and applies the impact force of F. The force/wave travels the distance L through the mass at the end of which there is a wall so I think the force attenuates. Assume we have all the properties of the mass. My question is, what...

Hello, for my PhD, I've been studying an influence of a gain medium on spectral linewidth of light inside a fiber cavity. I've encountered a formula in one paper to which I don't how to get to (see screenshot), it's the formula (A3). On the left hand side there is electric flux density, the...

I first thought that the angle would have to be maximum when it is closest to the critical angle for total internal reflection. From my lectures the equation for the critical angle is ##\theta _1>\ sin ^{-1} \left( \frac {n_2} {n_1} \right),## so as ##n_2 = 1##, we have ##\theta _1=\sin...

hello everyone I read this text in physics book: "Another example is the so-called Cerenkov radiation, which consists of light waves emitted by charged particles that move through a medium with a speed greater than the phase speed of light in that medium. The blue glow of the water that often...

Hi, I know the usual formula for both moving source and receiver in a static medium (from wiki): Is ir correct? What about when the medium is moving too? I can't seem to find an answer, and worst, I'm finding contradicting ones. For example, when the source and the receiver are moving at the...

1.) In electromagnetics, wavelength in a medium is $$\lambda = \frac{\lambda_{0}}{n}$$, where $$n$$ is the refractive index. What is the equivalent formula for sound wave in a medium? 2.) Is there a reference sound velocity, like electromagetic wave speed in vacuum is $$c_{0} =...

If light goes from air through glass, the reason the light bends is because I'm told that the light travels slower inside the glass. If I change my observer reference to inside the glass, the speed of light inside the medium it look like light is still traveling at the speed of light? if so, the...

Hello everyone. I have just complete an experiment calculating the speed of a muon. I got it to 2.6E8 m/s, however I know that they are created at close to speed of light to be able to get down to Earth's surface in their short lifespan. This speed could not have been its initial speed, as it...

> A diffraction grating, ruled with 300 lines per mm, is illuminated with a white light source at normal incidence. (ii) Water (of refractive index 1.33) now fills the whole space between the grating and the screen? What is the angular separation, in the first-order spectrum, between the 400 nm...

The force on charge ##q_2## will depend on the electric field in medium with dielectric ##K_2##. Electric field in this second dielectric due to ##q_1## is ##E = \dfrac {kq_1} {K_2r^2}## where r would be the distance from ##q_1##. So, the electric field at the point where charge ##q_2## is...

I imagine a particle traveling across 1 wave cycle. The total vertical distance traveled across the wave cycle is 4 x the amplitude of the wave. The total vertical distance traveled in 1 minute: 5 cycles in 1 second, thus 5x60 cycles in a minute then 4 x amplitudes effectively traveled per...

I have a lot of acorns in my pebbles. I'm looking for a way to sort these out quickly. I was thinking of the possibility that something floats on water and another material does not. If I use plain water, most of these acorns will sink too. So my questions is how much salt or other product...

I once naively think that the speed of light is also a constant in a medium in all inertial frames which is not the case. I tried to derive the result yet there is a discrepancy from the results I read in some articles. For example, from [Link to unpublished paper redacted by the Mentors], the...

Hi there, here's the problem: There's a sound, with a certain frequency coming, from a source. Both the listener and the source are fixed in a inertial reference frame. But there's wind blowing from the source to the listener. Now, this situation isn't the same as the listener chasing the...

I would like to conduct a thought experiment. If some form of medium exists, what would it be made of? What form would any constituent parts take? Would those parts exhibit any properties? How would they function as a medium? What relation would the medium have with atoms and other particle...

Hi hi, I'm looking into how temperature affects waves, but I don't know too much about this, in how temperature mixes with all of this, I have this questions: We have a particle vibrating at frequency ##f## at a certain temperature ##t_p##, and a medium with other temperature ##t_m1##. If the...

Calculate the wavelength for an ##E_x## polarized wave traveling through an anisotropic material with ##\overline{\overline{\epsilon}}=\epsilon_0diag({0.5, 2, 1})\text{ and }\overline{\overline{\mu}}=2\mu_0## in: a. the y direction b. the z direction Leave answers in terms of the free space...

It is an open question. The professor asked us to find a suitable method to solve it with the help of a computer. When I learned the Mie scattering, the equations are given for particles in homogenous medium. But now half of the particle is surrounded by glass while the other half by air...

The answer to (c) is ##-2\pi AGMm##. Answer to (d) For sub-question d, I used a different approach and I don't know why the solution to (d) is an appropriate approximation. What I did was that I use Newton's laws to obtain two differential equation in polar coordinate, as shown: $$\text{Assume...

I answered the first part of the question where I estimate the radius of ##O_{2}## is ##\approx 1.5 \times 10^{-10} \ \text{m}##: $$ p = \frac{KT}{l 4 \pi r^{2}} = \frac{(20+273.15)(1.38\times 10^{-23})}{(0.1)(4\pi)(1.5 \times 10^{-10})^{2}} = 0.143 \ \text{Pa}.$$ The confusion arises on the...

What are the types of thermodynamics processes that happen in solids or continuum medium

Good afternoon, I have a question regarding this derivation that I'm covering in Thornton & Marion's "Classical Dynamics of Particles and Systems". In it, we're covering the most basic equation of motion for a particle falling in a medium. I understand the process of starting with Newton's 2nd...

When traveling into an optically denser medium, the speed of light reduces and as per the principle of least time, light bends towards the normal and takes the shortest path. But why isn't this followed when light passes into a rarer medium? With its speed increased in the rarer medium, if it...

Hello all, Apologies in advance for the text-wall; this is a rather involved question. I am trying to compute the effective transmission coefficient for a medium of non-uniform refractive index. For simplicity I am assuming the slab has thickness ##d##, that ##n(0)=1##, and that ##n(d)=n##...

I gather that special effects artists sometimes use a sculpting medium called "hybrid clay". (Unfortunately, web searches about it are impeded by the use of the term "hybrid clay" as a hair conditioning product. Sellers of sculpting materials do use the term - e.g...

When light travels through a medium like water, it slows down and its speed is no longer equal to c. How does this affect the life time of the photon?

I was just thinking on the fact that there are some comercial gas masks . These ones have a filter, that doesn´´´'t let the Hydrochloric acid gas molecules to go into the mask. This is the way it basicly works, isn't it? So this filther has some little holes that are smaller than these...

This means the sound wave reaches the outlet faster as it travels in the same direction as the medium. But I was reading online that speed of sound is independent of the medium so I don't know why my professor used this approach. If speed of sound was dependent on the medium, then wouldn't shock...

If a medium with speed of light ##c_1## is considered, shall the Lorentz transformation be considered relative to it or to speed of light in the vacuum ? I don't know if we could send particles like muons through water for example, to check this with their life time.

Why is speed of light in matter medium smaller than speed of light in vacuum?Are all photons must be absorbed by atoms and then the atoms re-emit radiations in matter?What is real picture of all photons in transparent medium?

I am reading Landau's Vol 5 on Statistical Physics and have trouble grasping some concepts in Section 20. If I understand this correctly, the body and the medium are in direct contact and can exchange work and heat while the object can only exchange work with the body. So the minimum...

Summary: What can we tell about the medium a wave has traveled through? What can a wave tell us about the media, whether it is space, water, air or whatever, that it has passed through? Does it have some "memory" or hint of what it has previously passed through? I am thinking mostly of...

In a regular quadrangular pyramid the area of a side surface is twice as much as the area of the base. Find the ratio of the height to the length of the side of the base of the pyramid.

Hi, I was wondering what would happen with the interference pattern if I had a medium with higher refractive index than air in front of the slits. Would the interference fringes become narrower?

I don't know where to even begin?

I know that the speed of light is different in different mediums. The speed of light in Cesium as a medium is actually higher than the speed of light in vacuum. How is that possible? Shouldn't it be fastest in vacuum? [Mentors note: this post has been lightly edited as part of splitting it out...

Hi, I'm reading chapter 6-3 of Lamarsh's book "Introduction to Nuclear Reactor Theory". Here it is discussed the very idealistic case of Hydrogen being used as a Moderator (without adsorption). The moderator is: - infinte - homogeneous - with uniformly distributed source emitting at constant...

EM waves can propagate through empty space, but there is also the EM field. Is this field really empty space or is there something that exists that the light wave disturbs, like some kind of fluid? In areas of space where values of the field is 0, is this like empty space or more like calm...

Homework Statement When a point charge is positioned at the origin = 0 in an isotropic material, a separation of charge occurs around it, the Coulomb field of the point charge is screened, and the electrostatic potential takes the form \phi(r) = \frac{A}{r} \exp\left( -\frac{r}{\lambda}...

When light, traveling through a rarer medium, gets reflected off at an interface with a medium of higher refractive index, it suffers a phase shift of half-wavelength. Now if it was normal incidence, the phase-shifted light would retrace its path. Does that mean the wave would cancel out?

I wanted to ask whether it might be feasible and advantageous to use an expansion medium other that water to go from liquid to vapor to turn a turbine to generate electicity in a reactor. Because of water's very high specific heat and heat of vaporiaztion, would it be possible find another...

I am looking for an optical piece that can act as a mirror when the angle of incidence is close to normal (90 degrees) but acts as a see-through glass when the angle of incidence is less than 60 degrees? Alternatively it can be a filter placed in front of a mirror that passes a lot of light at...

Homework Statement I read in my textbook that the force exerted by a charged particle q1 on another charged particle q2 does not depend on the medium between them. Yet we multiply ε by ε(r) in coulomb's law when there is a medium present between the particles. Can someone please explain this...

Hi, I am wondering if anyone could point be to any references for gradient optics. The current literature seems a little haphazard. The model I am looking for would need to consider the following. Single medium whose optical density (index of refraction) is some gradient index of refraction...

Famously em waves are an example of the latter case. The two cases (waves in a medium vs waves propagating without a medium) seem at first (to me) to be extremely different and perhaps only connected by their mathematical descriptions. I can think of two cases of waves without a medium...

...at the same speed in all directions? Suppose we are an observer floating "stationary" above a body of water moving in a straight line . We drop a weight vertically into the water and cause a wave to propagate out from the point where it meets the water. If we have two additional...

Good afternoon, I have read that light changes it's wavelength when it enters a different medium because it's speed changes but then I read that the speed of light doesn't change (it's always c) and it just takes longer. So, it is the "observed" wavelength that changes or some such? Any help is...