Electromagnetic waves Definition and 322 Threads

Can the magnetic wave have an influence on the electric wave?

Homework Statement In what units is energy density measured? 1. Watts 2. Watts per cubic meter 3. Newtons per meter 4. Joules per cubic meter Homework Equations E = cB (as derived by Maxwell) The Attempt at a Solution This question is so basic yet I'm confused. I thought...

This is a question about electromagnetic waves and gravitational waves. Let's say we're on the Earth and we're looking up at the sun (safely). If the sun were --for some reason-- to violently and dramatically jerk from its position, how would we first find out? Would we first *see* the...

My book takes a look at the maxwell equations in free space, shows that E and B satisfies the wave equation and then guesses on a plane wave as a solution such that you get a tranverse wave with E and B perpendicular to the direction of propagation. I don't know if I am too slow in realizing...

I was watching the lectures on the MIT OCW course 5.111 where it was said that electromagnetic radiations are periodic variations of the electric field. Does it mean that when we are talking about electromagnetic radiation, frequency indicates how quickly do the electric fields change(their...

I am trying to figure out how I would go about finding the steady-state temperature distribution in an absorbing medium using the steady-state heat conduction equation: (1) -\nabla\cdot\left(K\nabla T\right) = q_{gen} where T is the material's temperature, K is the material's thermal...

Ive asked this question so many times on various forums and i feel there is a simple answer that i just haven't heard yet. I realize that an EM wave is represented as a sine wave, but from what i understand, that's not the physical motion the fields take. Let's say we take a snapshot at the peak...

I have seen the retarded potentials and what not, but what has always bothered me is why these field solutions reflect when they meet surfaces. I have looked and looked, but there seem to be no analytical explanations for this, only empirical ones. So my gripe is, since electromagnetic waves...

Let's say I have some source that generates a spherical wave that propagates outwards at the speed of light, and I have a vehicle that is charged. The wave will accelerate my vehicle periodically and eventually bring it to great speeds. Does this work?

I know they're represented as sine waves but what would they actually look like in space. they wouldn't actually physically go up and down and side to side like a sine wave would they? I have seen representations of sound waves, which i assume is a longitudinal wave, but not a EM wave.

Why does nickel reflect infrared, but gold does not? I've seen devices that shine infrared at a metal surface and measure the reflectance. They're mainly used for looking at thin film coatings. For example, you could have a metal part made of nickel, and thinly coated in gold. The gold...

Every book I ever read describes a electromagnetic wave as a phenomena generated by charged particles accelerating. This will produce a change in electric field that induces a magnetic field. But, due to Maxwell equations a change in magnetic field will also produce an electric field. So, if a...

This is just a conceptual question that I've been personally wondering about. So light has a magnetic field wave perpendicular to an electric field wave. I don't quite understand the magnetic field wave though. I thought that magnetic fields were not supposed to have a beginning or end. They...

Let's suppose that on Earth I have two devices which permits me to detect the gravitation produced and electromagnetic waves (photons) emitted by the Sun. Then, the Sun suddenly disappears. Which of the two devices will notice first that the Sun has gone, i.e. which wave propagates faster, the...

Homework Statement The figure below shows a plane electromagnetic sinusoidal wave propagating in the x direction. Suppose the wavelength is 56.0 m and the electric field vibrates in the xy plane with an amplitude of 20.0 V/m. (a) Calculate the frequency of the wave. (b) Calculate the magnetic...

I haven't been able to find any literature that answers this question in a pleasing way. Also, all sources on the internet are contradictory. If electromagnetic waves (out of phase since they are emitted by the gaseous atoms in discharge tube) sent through a diffraction gitter interfered with...

I was just thinking about electromagnetic fields and magnetostatics. Magnetostatics is the study of magnetic fields where they do not change or very little. I was wondering if a static magnetic field is still considered part of a Electromagnetic field? Since the magnetic field is not changing...

I am having trouble understanding how a light wave travels through a medium, such as the Earth's atmosphere when emitted from a light bulb... I have read some topics on the difference between transverse and longitudinal waves, but I am having trouble understanding how they exist. I can imagine...

I have trouble understanding the concept of electromagnetic waves. my textbook has the following explanation for electromagnetic momentum. It's not very clear to me. [ light reflecting from a perfect reflector will leave the surface with its initial momentum, thus having twice its initial...

So what i understand from my professor about the electromagnetic waves is this : an electric charge has an electric field E a moving electric charge induces a magnetic field B The electromagnetic wave produced is due to the moving charge which has both components E and B... But my...

Hi There is lots of text, but it is actually just a presentation of facts and thoughts to explain where I am in all this. There are two main questions: 1) Are the incident waves from a very distant source, say a star very far away, interfering with one another to create one or more resulting...

Hello, why the electromagnetic waves move up and down instead of just travel straight? When an electron go in a lower energy level it relases a photon, but where does this photon came from? Thank you!

Homework Statement A plane monochromatic electromagnetic wave with wavelength λ = 2.2 cm, propagates through a vacuum. Its magnetic field is described by \vec{B} = (Bx\vec{i} + By\vec{j})cos(kz+ωt) where Bx = 1.8E-6 T and By = 3.8E-6 T, and i-hat and j-hat are the unit vectors in the +x and...

I hope this is the right forum for a first year undergraduate problem! The problem I've been working on is here: http://i.imgur.com/IhTtL.png I think that I have the correct answers, but I'm not sure. I think that the energy densities of the E and B field components will be (0.5)(ε0)(E^2)...

Hi Much of what I am going to write in this post is based on what I have read and understood (with very, very limited knowledge of the subject) on the Internet. So, if I have been misinformed or I have misunderstood anything, please don't hesitate to correct me. I would appreciate it. As...

I like to know if electromagnetic waves pass through a medium (Glass) and if this medium were in contact with two other mediums in its boundary which the first one with same optical dense (Glass) and the second with less optical dense (air). Is there any tendency or priority for wave to pass...

I've always thought that photons and electromagnetic waves are one in the same. And I still do, but I'm trying to get a better grasp on the idea and am finding it difficult. 1) As I understand it, they are the same. But an electromagnetic wave with definite frequency is a perfect sine wave...

Hi all, I'm trying to understand exactly what the physical meaning of conductivity/current is in relation to waves. if we have a wave traveling through a conductor, we find that it decays exponentially, i.e. e^{-\alpha z} where \alpha=imag(k)=\omega\sqrt{\frac{\epsilon\mu}{2}}...

Hi everyone I have a question that has been bothering me for a while now. I have basically built a Faraday cage using wire mesh. I know there is a relationship between the mesh hole size and the wave suppressing ability of the cage. As I understand it an electromagnetic wave can be thought of...

Homework Statement Hi In Griffiths it is stated that any possible wave can be written as a sum of plane waves f(z,t)=\int_{-\infty}^{\infty}{A(k)e^{i(kz-\omega t)}dk} This is a sum over spatial frequencies. In another book I have, they write the H-field as H(r, t) = \sum_n{C_n H_n(r)\exp...

You know how a microwave oven has a mesh on the door so visible light gets through but not the microwaves? Can such a thing be done with infrared radiation too? Is it possible to block heat from getting through a mesh but not visible light?

Both are energy right? I'm asking cause I'm trying to understand the double-slit experiment and I'm just wondering how they can be sure to treat the electron as a particle. Could it be performed with for instance whole atoms or maybe the cores or something else that's more obviously matter...

I'm having some trouble understanding visually the propagation of an electromagnetic wave. I'm self-studying electrodynamics so I've never had someone explain this properly to me. I understand an electromagnetic wave is a propagating disturbance in an electromagnetic field. Originally, I...

Are the amplitudes of the electric and magnetic components of an electromagnetic wave proportional? Or is the amplitude of the electric portion unrelated to that of the magnetic portion?

Homework Statement Electromagnetic waves contain time varying electric and magnetic field perpendicular to each other and also to path of progression. The phase difference between electric field vector and magnetic field vector is zero Homework Equations The Attempt at a Solution...

A standing wave can be produced in a guitar string where the wavelength of the wave is the same length as the string (I believe this is referred to as the first harmonic) and where the string is an exact multiple of the wavelength of the wave (referred to as the second and subsequent harmonics)...

From: http://answers.yahoo.com/question/index?qid=20090223155307AAgqbWk Question: Why are electromagnetic waves transverse waves? Answer: "Because they are generated by the rapid vibration of elecrons, which go side to side, perpendicular to the direction the waves travel (very very rapid...

Electromagnetic waves consist of electric and magnetic fields having the same phase how?

Hey everyone, Im doing this research and reading this http://science.hq.nasa.gov/kids/imagers/ems/gamma.html" it had a diagram of the depth of penetration of different wavelengths into the eaths atmosphere... my question is, How come x-rays penetrate deeper than visible light - what is the...

If EM waves are pumped into a resonant cavity at it's resonant frequency will each incoming wave add it's energy to amplify the wave(s) in the cavity? I know that if you pulse a light source into a circular wave guide and you pulse the light source each time the light wave returns to it's...

Hello every one . We know Radio waves carrying data When a radio device receives radio waves , It render the waves and we hear sound . Now my questions are : 1 - How data on electromagnetic waves are transmitted ? When a electromagnetic wave hit a atom it absorbed by the atom like this...

why electromagnetic wave is transverse?

Electromagnetic waves, aka light and such. What is it?. I know that it is a wave of energy, magnetic and electric forces traveling in wave forms but when struck turning into a particle. But what exactly are they made of? Is it just a pure wave of energy and nothing else to it? Do physicists...

Hi guys, I am too old to remember basic knowledge about electromagnetic waves :D I am looking for a combination of an electromagnetic wave and a material such that the wave can pass through human tissues, but it is blocked by the material. All I know is that X-ray/gamma can penetrate human...

In the double slit experiment, a wave is forced to go through a tiny slit. I do not understand what is stopping it from going through the barrier. After all, we can think of an electromagnetic wave as just the electric/magnetic fields of a sinusoidally oscillating particle, evaluated using...

Homework Statement The average intensity of sunlight at the top of the Earth's atmosphere is about 1400 W/m^2. What is the maximum energy that a 20 m × 30 m solar panel could collect in one hour in this sunlight? Homework Equations Not sure what equation to use The Attempt...

Hi PF Are there an interaction between an electromagnetic wave and a charge source? For example, does an electromagnetic wave get attracted by a charge source, the same way the Earth attracts the moon? Or is something else going on?

i really want to understand the lesson so bad i read the lesson 10 times and the lesson is like 50 pages and i still don't get the concept of how electromagnetic waves were originated?? and what about polarization? please with all the details you have and thank you

Homework Statement A laser beam of power P and diameter D is directed upward at one circular face (of diameter d < D) of a perfectly reflecting cylinder. The cylinder is levitated because the upward radiation force matches the downward gravitational force. If the cylinder's density is ρ...

Hi, In electromagnetic wave, electric field take the form E(z,t)=A q(t) sin(kz) where A is a constant, k is a wave number, and q(t) is a time dependent factor having the dimension of length. This mean that q is a position..but position of what ?? Is a position of the wave ?