Em radiation Definition and 89 Threads

Why isn't EM radiation attracted/repelled by a magnetic field?

Hi, I wanted some clarification on the mechanism for how EM radiation interacts with standard glass, namely IR, visible and high energy (UV and X-ray). Looking online most sources seem to say the band gap is around 10eV. Since visible light is about 1-3eV visible light will be transmitted. IR...

Picture: Energy source => LR Oscillator => Transformer => Transmission line => Electric dipole antenna => traveling wave Why would the charge even oscillate in the antenna as opposed to building up in the antenna? The transmission line + antenna is not a closed circuit right?

Electromagnetic radiation is propagating sinusoidal electric and magnetic fields. Are the peak amplitudes of these fields in any way related to the radiation's other parameters, e.g. its instensity?

Having had a look at the following video of the dipole antenna and the creation of EM radiation, which I completely understand, I had a look at the link http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/procyc.html#c1 and the hydrogen fusion process within a star. Looking at the process how do...

I took Inorganic Chemistry I and Physics in high school. I took Inorganic Chemistry I and about half of Inorganic Chemistry II (dropped out mid-semster of Inorganic Chemistry II) in college. My Physics class in high school was just regular physics, not AP Physics, so I have never taken a...

Suppose there are two free electrons. Their mutual repulsion causes each to accelerate. Is there EM radiation? Suppose those electrons are loosely bound to a nucleus, as in a metal. Is there EM radiation?

I just realized I'm having a problem in understanding this. So let's take an example the CMB is around 160 Ghz and the blackbody temperature within this frequency range is 2.7K which is rather cold as it is close to absolute zero. Then let's take another example, Iter plasma will achieve about...

Hi All In discussing another issue it occurred to me the only experiential evidence I know that normal visible light is EM radiation is Faraday Rotation. I strongly suspect we have a lot more these days. Amusing story. Fermi's wife had a degree in general science that did not cover...

Hi, Source: https://en.wikipedia.org/wiki/Second#"Atomic"_second How were such huge number of periods per second measured originally? Was an instrument such as Michelson interferometer used? I think it was Albert Michelson who invented the interferometer to make calculations of wavelength and...

As I understand it, it is the magnetic part of electromagnetic radiation which creates a current (AC) in a radio receiver (i.e in an antenna) which can be translated into sound/graphics and so on. Is this correct? I mean in the sense that it is the magnetic field in the incoming radiation which...

I don't know where to even begin?

So I see EM radiation , visible spectrum including being portrayed as two sinewave vectors each perpendicular to other one being that of the E field the other being the B field, the field is carried by photons, let's take the visible spectrum as an example. So having a specific frequency the...

It's my understanding that deforming a piezoelectric crystal causes electric charges to build up on the outer faces of the material. What I would like to know is if these charges behave like the free charges in a metal. More specifically, does deforming a piezoelectric crystal effect how em...

Am I correct that the direct proportionality between the energy and frequency of an EM wave can be obtained from classical electromagnetism? Of course there's the Planck–Einstein relation ##E = h \nu## for a photon, but that entails QM. I'm wondering about the relation ##E \propto \nu## for an...

What is the best analogy to explain electromagnetic fields? I have seen the depictions of em radiation as perpendicular waves. Do we exist in a huge sphere of em radiation in which waves such as cell phone signals and radio broadcasts can be thought of as spherical ripples that emanate at the...

Suppose I were to subject a polar molecule to a high-frequency electric field. The polar molecule responds to the high-frequency electric field and thus it has a time-varying electric dipole moment vector. If we treated this as a classical electric dipole, it would be expected to radiate some of...

Homework Statement Homework EquationsThe Attempt at a Solution From the equation it is clear that the wave is propagating in y direction. So, the magnetic field is along z- axis. ……….(1) Dimensionally B = E/v……….(2) According to the above two conditions , the correct option is (c). Is this...

Homework Statement Homework EquationsThe Attempt at a Solution E = (13.6 – 3.4 = 10.2)eV = ## \frac {hc } { \lambda } ## =1.22 * 10^{-5} cm So, the correct option is (a). Is this correct?

Hello, I am a Mechanical Engineering student but I am a TA for an electricity and magnetism course, and I had a student ask a question that's a little bit outside my understanding. The question was related to the equation for a radiating electric field from an accelerating charged particle...

Bear with me, I am just a chemist. Observations took several days (up to two weeks if memory serves me well). What I wonder is - why had different types of the EM radiation came at different times? Gamma burst was observed at almost exactly the same time gravitational waves were detected, but...

A clump of charged particles moving in circular motion emits em radiation. But if I go on increasing no. of charged particles till the time the system becomes current in circular path, then since each particle is having same acceleration and velocity, the current will be uniform. So, now the...

Homework Statement X-ray pulses, visible-light pulses, and radio pulses (the latter corrected for dispersion in the interstellar plasma) emitted by an astronomical object called a “pulsar” are all observed to arrive simultaneously at the Earth — with an uncertainty of only 200 microseconds. The...

In the 1953 science fiction novel Childhood’s End by Arthur C. Clarke, characters use two crossed fields in outer space to block some of the solar radiation traveling towards earth: “Somehow, out in space, the light of the Sun had been polarized by two crossed fields so that no radiation could...

The following question/thought experiment is based on the dual nature (particle/wave) of electromagnetic radiation. Consider the emisson of a single photon on a 3D grid along the x-axis with its origin at (0,0,0). The only matter in this experiment consists of “electrons” found only in...

-iation. Could the opacity of a material to one band of EM radiation (light) could be altered by irradiating the material with another band of EM radiation (X rays)? I think you are suggesting that: By raising the electrons in the atoms to higher energy bands (with the X rays), so that they will...

I just had a flashback to an applied electromagnetic course I took a few years ago. I believe we were learning possibly about waveguides (maybe) or something, but there appeared a phenomenon in the math that made it appear as if the wave was traveling faster than C. When asked about it, the...

Hey all, is there a formula that can calculate the energy losy by a photon traveling through air at 1 atm per meter given frequency? Any help apreciated.

I think the equation for the relationship of the E (electrical) and B (magnetic) fields in electromagnetic (EM) radiation is E=Bc, where c is the speed of light. I think this is correct, but what does it tell us? On it's face, it looks as though the B field (of a photon, say) is...

How is energy dissipated in a traveling electromagnetic wave ? Will there be any dissipation if it were to travel through vacuum ?

For a photopolymer, the heuristic goes that longer wavelengths of UV light penetrate deeper than shorter wavelengths of UV light. For example, the UVA spectrum penetrates more deeply into the photopolymer than the UVC spectrum. What is the best way for this to be explained?

I might have learned what I am going to ask during my electrodynamics class long time ago but just that do not remember it now. I always wonder why does an electron moving in space with EM radiation have Hamiltonian of the form ## H = \left( \mathbf{p}-e\mathbf{A}/c \right)^2/2m +e\phi## where...

I have 2 questions about EM radiation produced by an occilating electric charge. Q1: With graphs of electromagnetic fields, you can see that it contains an electric and magnetic component. What does these mean or give information about? Q2: By occilating the charge, you will get such a graph...

An article in Wikipedia tries to explain pigments. One particular section has the following: "A wide variety of wavelengths (colors) encounter a pigment. This pigment absorbs red and green light, but reflects blue, creating the color blue." Questions arise... They may see stupid, but please...

Hello. I was taught that a charge which changes its velocity must radiate (at least, in classical electrodynamics). Let's consider a charged particle which decays into another charged particle (and, maybe, others neutral particles; but not photons). In this case, can we find electromagnetic...

I want to pump energy into a chemical species to increase its reaction cross section with another. Typically these species react upon collision when their relative kinetic energy exceeds the activation energy. I want to find a way to increase the reaction rate for interactions at slower...

Are gravitons and gravitational waves analogous to photons and EM radiation?

Energy Of A "Single" Photon In Em Radiation? Is the energy of all photons in em radiation same? That is, say light differs from radio waves only in the number of photons per second

Just a thought because of the anomalous Planck satellite cmb data, and the second largest continuous structure in our solar system that almost fried the pioneer probe... Jupiter's magnetosphere which is known emitting radiowaves.

for RF, how does this mechanism work? http://i.imgur.com/Crx4Amx.png how does the conductor do this? and why does the unpolarized RF not seep through the spaces between the conductive bars?

I'm looking for the general formula for Angular Momentum radiated away from quadrupolar electromagnetic radiation. I searched the usual books (Jackson, Landau-Lifchitz, ...) and just found the usual dipolar contributions. Using dimensional analysis and energy radiated away, I found this...

Homework Statement (i) What is the phase velocity of EM radiation in free space? (ii) What is its group velocity? Homework Equations The Attempt at a Solution Using the definition as per this page: http://physicsdaily.com/physics/Phase_velocity (i) Vp = (C^2)/Vg (ii)...

An electron and a positron annihilate and energy is released in the form of quantized EM (gamma etc.) rays: Now some childish yet inquisitive questions; 1. Where were there quanta prior to annihilation, inside the electron or positron (or both)? 2. Were these quanta really present...

Hello, I have always wondered, what the relation of wavelength and frequency to the amplitude is. Is there an equation? Does it vary with different types of waves? Can it change?

Pulsars -- Rotating neutron star produces EM radiation? Hello, If a neutron star is composed of neutrons, which do not carry any electric charge then how it's rotation produces pulsars which are electromagnetic radiation? Thanks.

If visible light is part of the EM spectrum just like radio waves, is it possible to construct a radio like antenna (metal pronged structure) to detect them?

Homework Statement 6. S1 and S2 in the diagram are effective point sources of radiation, excited by the same oscillator. They are coherent and in phase with each other. Placed 4.0 y m apart, they emit equal amounts of power in the form of 1.0 m wavelength electromagnetic waves. (a) Find...

Hi ,does anyone know a good book in advanced EM radiation and it contains more information on velocity EM field , I have already finished Griffith's book

the energy of em radiation (or photon) is proportional to the frequency of the radiation. the em radiation (or photon) is composed of oscillating Electric and Magnetic fields. as such this energy must be stored in the oscillating electric and magnetic fields constituting the radiation...

How are stellar EM radiation formed?? I've read this in many books and sites... Any object above 0 K will emit EM radiation of all wavelengths... Now this is confusing me a lot... I mean, how for example a sun emit wavelength s of a Radio and it is the same sun which emits ultra violet and...