Em wave Definition and 225 Threads

Hello All, this is my first post, and while I'm a newb to the forums I'm not a newb to Optics. However, I have a very light background in low level electromagnetics, I'm more of a network design person. I'm working on a very very long term personal project to understand optics better and I've...

Hi, I'm rather new here. I've got a question that's bothering me, and therefore decided to ask here. Why is it that in a lift/elevator, radio signal usually gets weakened? And, as far as i know, FM radio operates on the radio wave band, as well as cell phones. But why is it that mobile...

Homework Statement energy density in a laser beam is 9.5x10^-8 J/m cubed. the laser beam is cylindrical, and it delivers a power of 15W to a certain area. What is the radius of this circular area? Homework Equations Intensity : S=cu and S=Power/Area Area of a circle (or possibly the...

How an em wave propogates?? i understand that an em wave can be produced due to an oscillating electric field or oscillating magnetic field... but how does this wave move forward at the speed of light??

How does Electromagnetic waves travel in vacuum ?

Can a monochromatic plane EM wave exists in a plasma when \omega is less than \omega_p (the plasma frequency)? If so, is it attenuated? I read in a text that a wave incident on a plasma with \omega < \omega_p is completely reflected, but does this mean such a wave can't exist in a plasma? If...

Here is the question i am working on: An AM radio station broadcasts with average power 4000 W in all directions. A dipole receiving antenna 65 cm long is at a location 4 miles from the transmitter. Compute the amplitude of the emp that is induced be this signal between the ends of the...

Hi, if someone could help me figure this out I'd really appreciate it. Estimate the average power output of the Sun, given that about 1350 W/m^2 reaches the upper atmosphere of the Earth. I know the answer is 3.8 X 10^26 W but I don't know how to get there. I've tried different equations...

Suppose I have an eliptically polarizied EM wave, whose electric field can be written as \vec{E}=A\cos(kz-\omega t)\vec{e}_x+B\sin(kz-\omega t)\vec{e}_y, where the constants A and B are amplitudes of the x and y components of the beam, respectively. How would I report the amplitude of the...

I'm not sure if this belongs here or in the relativity forum but associated with an electromagnetic wave is a magnetic field B and the force of this field on a charge q with velocity v is qv x B. Since any charge will be moving with speed c relative to the wave, will the magnetic force on a...

I've read in a book, that if you had a standing electromagnetic wave between two metal plates, only nodes would be at the metal plates. This is due to the infinite high conduction of metal, the book says. Why is that so?

argh hello guys, I've been trying to find out a simple answer to this question but all the resources I've looked at seem to skim over it or contradict each other, but simply: Do electromagnetic waves have a variable amplitude? "Intensity" is not necisarilly the same, if you're using the...

Hi, My question: Explain how an electromagnetic wave is produced? My Answer A charged particle produces an electric field. the electric field exerts a force charged particles. Positive charges accelerate in the direction of the field and negative charges accelerate in the direction...

hi guys i had a quick question about EM waves given EM traveling west, B field oscilates vertically and has f= 80,000 Hz and a rms strength of 6.75e-9 T what are the frequency and rms strength of electric field and what direction... so for direction i have it...

Does EM wave have to actually strike a surface to induce current or can the EM fields induce current from a distance?

Please link me to threads that may already discuss this because i do not really know what to search for when i use the word substance. I neglect to use the word matter because matter in physics world means mass and i neglect to use the word particles because in physics world they usualy...

Suppose a 50-kW radio station emits EM waves uniformly in all directions (a) How much energy per second crosses a 1.0m^2 area 100m from the transmitting antenna? (b) What is the rms magnitude of the E field at this point, assuming the station is operating at full power? (c) What is the voltage...

Hiya, Given that the electric field vector of an EM wave is described as: E=E_0[1+\cos(\Omega t)]\cos(\omega t) How would one go about finding the energy carried by this wave? On another note, what's the actual frequency of the wave that can be used in E=hf ? Graphed in a CAS, this wave...

The similarities between the classical wave packet and the QM photon are striking. They both move at the group velocity. They both are subjected to an uncertainty principle. A classical wave packet is like a photon a region of concentrated energy, ... So is a photon something like the...

Hi, I wonder how the electron's position energy reflects the electro magnetic wave's frequency. Daniel

i learned that EM wave is varying electric field and magnetic field .But what's the meaning of the amplitude of EM wave? The displacement of the photon or the magnitude of the electric/magnetic field(no. of photons)?

A simple question. I though Maxwell said that : 1. The change of electric field generates magnetic field. 2. The change of Magnetic field generates Electric field. So, simple algorithm tells me there shall be a 90 degree of phase difference between the peaks of E field and B...

What is Light? What is Light? Is it a EM wave or a stream of photons? Is there any theory which can explain all the phenomena of light? P.S.: Another question, What makes glass transparent?

Im not sure of this, but visible light is an EM wave just like radio waves are, right? If I am right, does that mean mirrors reflect all ranges of EM waves, radio included? Also what is it about a mirror that reflects photons?

-> http://electron9.phys.utk.edu/optics421/modules/m1/production.htm Hmmm... If U &prop; E2, E &prop; a and a &prop; &omega;, how can Uavg not be dependent on [b]&omega; ?