Electromagnetic wave Definition and 197 Threads

1. The problem statemeent, all variables and given/known data The field electric's electromagnetic wave issued by a strut isotropic source is: \vec{E} = E_{0} r_{0}*cos(ωt − kr) \vec{θ} Find the magnetic field in spherical coordinates Homework Equations I think, i use the equation \vec{B} =...

Imagine a mass that disappeared from space. I know that it is impossible, but imagine it is sucked by a wormhole or it just disapperars. Will we detect ONE gravitational wave only? Like a pulse and nothing else? Now the other way around. A mass appears from nothing. Then we will detect one...

In my physiology (biological science) class it was explained that, upon eating some food source, some energy is converted into a useful form for the body, and some energy is lost in the form of heat. The lecturer didn't explain what form this heat is in. I thought that 'heat' must be an EM...

Suppose you have a solution to the Maxwell's equations in vacuum, and now you want to find what kind of charge/current system create the wave in the first place, can this be done?

Consider the problem shown in the "wave_incidence_1.png" attached image. An electro-magnetic wave is traveling towards an interface between its current medium and a new medium, which has a refractive index n_2 \neq n_1. The interface is represented by the (x,y) plane. The electric field...

I've heard that em wave consists of mutually perpendicular electric & magnetic oscillations. Imagine that I've a unit charge at any point in space. Associated with this charge, there exists an electric field which diminishes with distance from the charge. If we set forth an oscillation in this...

Homework Statement A monochromatic, electromagnetic plane wave is traveling in a non-conducting, transparent medium. Its real electric field is described by: ##E=100 \ cos (7.62 \times 10^6 (x+y+z) \ - \ 2.98 \times 10^{15} t) \ \frac{1}{\sqrt{5}} (\hat{y} + 2 \hat{z}) \ V/m## (a) What would...

Homework Statement If the magnetic field of a light wave oscillates parallel to a y axis and is given by ##B_y = B_m\ sin(kz- \omega t)##, (a) in what direction does the wave travel and (b) parallel to which axis does the associated electric field oscillate? Homework Equations The Attempt...

Electromagentic waves travels at the speed of light that is 3.0 × 10^8. Is the light itself is electromagnetic wave because if the light is a transverse wave which is the electromagnetic wave is transverse too does that makes the light as an electromagnetic wave ?

will the distance traveled by an em wave depends on temperature,if so then explain

Homework Statement A sinusoidal electromagnetic wave from a radio station passes perpendicularly through an open window that has area of 0.700m2 . At the window, the electric field of the wave has an rms value 2.30×10−2V/m . How much energy does this wave carry through the window during a...

Homework Statement For an electromagnetic wave with an electric field given by \mathbf{B}=\mathbf{i} E_o cos (kz-\omega t)+ \mathbf{j} E_o sin (\omega t - kz) where Eo is a constant Find (a) its direction of propagation (b) the magnetic field (c) Poynting vector (d) energy density, i.e., the...

Did James Clerk Maxwell Ever Draw a Picture of an Electromagnetic Wave in any of his notebooks? Who was the first one to draw one? Would love to find the first picture representing it all! I am looking for the first example of a drawing looking like this showing the perpendicular sinusoidal...

Consider two frames: S and S', with S' moving to the right along the positive x-axis or S at a relative velocity v. The origins of S and S' coincide at t = 0. A spherical electromagnetic wave leaves the origin of S the moment S and S' coincide, or at t = 0. If we consider the transformation...

Caution: I'm new at this stuff. On page 573 of Gravitation (Misner, Thorne, Wheeler), they write down what I think is the electromagnetic wave equation for a discussion on Optics, "Next insert the vector potential (22.25) into the source-free wave equation (22.19d):" I am wondering if the...

Homework Statement Show that the solution \textbf{E}=E(y,z)\textbf{n}\cos(\omega t-k_xx) substituted into the wave equation yields \frac{\partial^2 E(y,z)}{\partial y^2}+\frac{\partial^2 E(y,z)}{\partial z^2}=-k^2E(y,z) where k^2=\frac{\omega^2}{c^2}-k_x^2 Homework Equations See above. The...

My textbooks says in a region where there is no charge or current Maxwell's equations read divergence of E=0 Curl of E=-dB/dt all d are partial Divergence of B=0 Curl of B=ue(dE/dt) I get the math of showing that there are waves, but I don't get some of these conditions. 1st don't you...

Is it possible to solve these partial differential equations directly, relating to Antenna Theory; ∇^2 E - μ_0 ε_0 \frac{∂^2E}{∂t^2} = -μ_0 \frac{∂J}{∂t}. AND ∇^2 B - μ_0 ε_0 \frac{∂^2B}{∂t^2} = -μ_0 ∇ x J. I don't like the idea of having to make up fields that don't exist in order to make...

Hi PhysicsForums, I was wondering if this youtube was a correct representation of a photon traveling through space with time. What I am trying to grasp is that, is the photon creating a trail of static Efields and Bfields as it moves through space as shown in the youtube, or does the...

I’m not asking about the duality particle/wave behavior. I just want to know when did the notion of light being an electromagnetic wave first came up. Was it before or after Maxwell’s calculations of the speed of waves? I am currently reading a book that explain the process by which Maxwell...

https://www.physicsforums.com/showthread.php?p=2881300#post2881300 According to the quoted thread above and according to textbooks and Wikipedia the phase between the E and B fields of an electromagnetic wave propagating in free space is zero. This assertion is based on the Maxwell equations...

Hello! I am not quite sure how do i verify the complex wave function of EM wave \vec{E}(x,y,z,t)= \vec{E}0ei(kz-\omegat+\delta) is a function of the wave equation \nabla2\vec{E}=\frac{1}{c^2}\frac{∂^2E}{∂t^2}

So if an EM waves travels from one medium to the other, it refracts depending on Snell's law. But what happens when it doesn't travel from one to the other, but goes right along the boundary so that one end of the amplitude is in each medium? As the wave "waved", would it have different speeds...

Homework Statement An electromagnetic planewave (non-monochromatic) propagates in vacuum along the positive x axis. The electric field vector is parallel to the y axis. We know the dependence of the component E_y on the variable x at the moment t = 0: E_y(x) = E_0\ \text{if}\ |x + a| < b...

I'm reading about electromagnetic waves and I can't make sense of their self-sustaining nature. If a charge accelerates for a moment and then stops a disturbance in the electric field is sent out. This changing electric field creates a changing magnetic field and they continue to sustain each...

I have a couple questions pertaining to electromagnetic waves and Maxwell's equations. I will list them numerically, for clarity: 1. From the textbook, "once [wave] is created it is self-sustaining and independent of the source." Is this statement only true when it exists within a vacuum? I...

Homework Statement Hey guys. I have an electromagnetic wave traveling in the z direction and polarized in the x direction. The frequency is 1 MHz and average power density is 1 W/m^2. An antenna in the shape of a circular wire is in the xy-plane centred at the origin. I would like to use...

I'm trying to teach myself some basic physics, and so maybe this question is stupid! But according to the wave model, the energy in an EM wave is proportional to the energy in the E and B fields, which can assume a range of values, no? But according to the quantum model, the energy of a photon...

I am a biochemist and so my physics knowledge is limited. But for a long time I have been wondering on how exactly the electromagnetic field associated with a single photon propagates in space. I understand (using a cartesian image of the electric and magnetic field change) the oscillating...

Homework Statement GPS determines your distance from a satellite by measuring how long it takes an electromagnetic wave to travel from the satellite to you. Imagine that a satellite is located at a distance of 127.2km and is moving away from you at a speed of 12.0km/s. a)how long will it...

Homework Statement Homework Equations The Attempt at a Solution Do I set up a proportion to first find the frequency of the electromagnetic wave in glass? 1.33/(3.42*1014)=1.62/fglass= 4.17*1014

Greetings everyone, I need information about how semiconductor interacts with electromagnetic radiation, the absorption, scattering, transmission and reflection properties of semiconductors. I also need to associate this information with free charges or bound charges. I would be grateful for...

Dear all, I am a newbie in electromagnetic wave. Can you educate me, what will happen when an electromagnetic wave is blocked by a piece of flat metal placed in front of it? My intention is to build a thermal chuck using peltier for to measure femto amps from my device. I am worried if...

What is the quantum of an electromagnetic wave? Quantum of light is photon. What is the quantum of a gamma ray or an X-ray?

So I've seen this equation used to calculate the energy associated with an electromagnetic wave: E=hf E is energy, h is a constant, and f is frequency. Therefore, the energy is related to frequency alone. However, why wouldn't the amplitude of that wave have an effect on the energy? I...

Hey! How to transform the equation \bigtriangleup\vec E=\operatorname{div}(\operatorname{grad}(\vec E))=\epsilon_0\cdot\mu_0\cdot\frac{\partial^2\vec E}{\partial t^2} in Einstein Notation? Thank you all for your help!

I have indirectly sought the answer to this for some time (since I studied an introductory course in optics 'long' ago), but nobody has been able to give a satisfactory answer, and I have not been able to find the exact answer on the Internet either. My question is about optics, and more...

Gamma ray can use to kill tumour because of higher frequency and therefore higher energy. The energy here is the number of time of the wave hit on the tumor or the amplitude of wave ? Thank you.

What is the relationship between photon and electromagnetic wave? I am trying to understand light, it is so weird. Light is not an electromagnetic wave, since it has different speed in different mediums. Light does not have mass (the mass that can be derived from the energy is not a real mass)...

Can I assume that anything with high enough speed will generate electromagnetic wave? Photons are not charged. But maybe because they move fast enough, they generate vortex electric field, since this field is changing, then you have a corresponding magnetic field with it, so you have an...

Homework Statement Prove that the electromagnetic wave equation:  (d^2ψ)/(dx^2) + (d^2ψ)/dy^2) + (d^2ψ)/(dz^2) − (1/c^2) * [(d^2ψ)/(dt^2)]= 0 is NOT invariant under Galilean transformation. (i.e., the equation does NOT have the same form for a moving observer moving at speed of...

ElectroMagnetic Wave In Liquid.. Help with Index of Refraction?? Homework Statement Consider the propagation of an electromagnetic wave in some liquid. The y-component of its electric field is given by Ey(x,t)=4.3 x104 V/m sin(5.40E-2m-1x + 6.00E+0 x106 s-1 t). How large is the index of...

Dear friends i know that a wave is linearly polarized if its components have a phase difference of n*∏ and is circularly polarized if phase difference is n*∏/2. But what if phase difference is neither ∏ nor ∏/2? like for E= ax exp(-j(βy-∏/4)) + azexp(-j(βy-∏/2))... thanks in advance...

An electromagnetic plane wave has an electric field and a magnetic field. Each component contributes equally to the energy density. Mathematically it is very straight forward to show this is true. The question is, "Fundamentally, why is this true?" Again, I'm not looking for a derivation...

Hey all, just wondering over a very naive question but I couldn't really find the answer by looking through the web. So electromagnetic waves are self sustaining and they don't lose energy while traveling through space, except if the photons they're made out of do "collide" with matter which...

At one instant, the electric and magnetic fields at one point of an electromagnetic wave are E = (210 + 320 − 40) V/m and B = B0(7.5 − 7.5 + a) μT. Find a and B0 E=cB The Attempt at a Solution So I found a using E dot product B = 0 and I got the value a=-20.625 and this is...

When an electromagnetic wave hits a conductor the transmitted part of the wave is damped considerably. I want to know if anyone can explain physically why the field is attentuated inside the conductor - i.e. what happens. I know the basic properties of a conductor: - Electrons free to roam -...

Lets take visible light for example. The frequency/wavelength determines the amount of energy and the type of wave(micro,radio,gamma ect.) The intensity or brightness is determined by the amount of photons. So what does the amplitude determine?

I can't represent me mentally what is an electromagnetic wave. I know that a mechanical wave is the propagation of a disturbance in a material medium and mentally I can see what it is. But electromagnetic ... Last year, I did electromagnetism. We studied Maxwell equations and we saw a...

I was curious about electromagnetic waves and whether or not they can be canceled in the fashion I require. First I will state a few principles that I am considering in the paragraph below and the paragraph after will pose the question in full. A Wireless router produces a signal that...