Electromagnetic waves Definition and 322 Threads

i have a problem i have been wrestling for past day. Radiowave transmitter on Earth radiates sinusoidal waves with whole power of 50kW. we have to presume that radiation is equally distributed to upper surface. And i have to find amplitude of E and B 100 km from earth. I derived equation that...

How many kinds of electromagnetic waves are there in the Universe? And what are they?

Hi, I have a couple of questions here I am having a little bit of difficulty with. 1) What is the wavelength of an X-ray that has a period of 1.30x10e-10s? 2) A certian EMR has a wavelength of 2.14x10e-5m in air. What is the wavelength is water(n = 1.33)? I am not looking for the...

This may sound dumb but... since light is classified as an electromagnetic wave, it has an E field and a B field. But doesn't this mean the E field will attract metal, and the B field will cause currents to flow? And since E = F/c = V/m does that mean the emr has a "voltage" or a "force"?

If light is transmitted as photons... and all light is is electromagnetic waves... is it accurate to say all electromagnetic waves travel as photons?

From Griffiths: Problem 9.4 Obtain Eq. 9.20 directly from the wave equation, by separation of variables. Eq. 9.20: f(z,t)~ = integral [-inf, inf] A~(k)e^i(kz-wt) dk where ~ denotes the complex conjugate the wave equation: f''(z) = (1/v^2) f''(t) I'm a little confused on how I can...

Lasers have been used to suspend spherical glass beads in the Earth's gravitational field. a) A black bead has a mass of 1 micrograms and a density of 0.200 g/cm^3. Determine the radiation intensity needed to support the bead. b) If the beam has a radius of 0.200 cm, what is the power...

Let us model the electromagnetic wave in a microwave oven as a plane traveling wave moving to the left, with an intensity of 26.6 kW/m^2. An oven contains two cubical containers of small mass, each full of water. One has an edge length of 6.40 cm and the other, 12.8 cm. Energy falls...

I have a question given to me by my professor: Which statement is true concerning a sinusoidal varying electromagnetic wave? a) The energy in the wave is mostly associated with the electric field because the magnetic field has a very small value. The reason for this is that B=E/c and "c"...

What are the Electromagnetic Waves used for in Electrical Engineering?

What are the factors that govern the diffraction of electromagnetic waves. Why is it that ordinary light diffracts so much while laser is so precise. Does it have to do something with the monochromatic character of laser?

I have a project but problems in formulating... the project is about the conductivity of a charged metallic body which is spinnig on a fixed axis. I am trying to find out whether there is a relationship between the characteristics of the electromagnetic waves emitted by the body and the...

What process within a star causes it to emit electromagnetic waves (light, x-rays etc.)? What is the source of the electricity / magnetism inside the star?

First here is the question: Who will hear the voice of a singer first? A person in the balcony 50m away from the stage, or a person 3000km away at home whose ear is next to the radio? How much sooner? Assume the mic is a few cm from the singer and the temperature is 20 degrees celcius...

How do electromagnetic waves propagate ? The explanation that is normally put forward to this question is that EM propagates through the self sustaining or oscillation of the electric and magnetic fields , which both support each other. As the electric field recedes the magnetic field...

Just wanted to know if someone could help me out or check my answers. The Transformer 38) A step-down transformer is used for recharging the batteries of portable devices such as tape players. The turns ratio inside the transformer is 13:1 and it is used with 120V (rms) household service. If...

Hi there Physics masters! How on Earth do electromagnetic waves expand at the speed of light to infinity (in vacuum) if we've learned that the electric and magnetic fields vary inversely proportional to the square of the distance? I don't know if it's a stupid question but I'm quite...

Problem 6. Radiation emitted from human skin reaches its peak at wavelength=960um. How much energy is carried by one quantum of these electromagnetic waves? Answer in eV. I have found that the frequency is 3.125*10^11 Hz. Note: What do I do? Problem 8. Light of wavelength 350 nm...

I have read briefly about polarization of electromagnetic waves and from what I understand an electromagnetic wave is said to be polarized in some direction if the E-field is aligned along this direction.. what then is unpolarized light?? - the E-field has a definite direction at every point...

Help me... A sinusoidal electromagnetic wave from a radio station passes perpendicularly through an open window that has area of .5m^2. At the window, the electic field of the wave has rms value of .02 V/m. How much energy does this wave carry through the window during a 30sec commercial?

show that electromagnetic waves in a vacuum are transversal waves. transversal waves mean that the electric and magnetic wave fields are always perpendicular to each other and to the direction of the wave propogation... but how does this link to a vacuum? and how can you show that a field...

Hi, I'm new. From what I understand, radio waves are generated these days using alternating currents or mechanically moving charges. The highest frequencies that modern technology reaches is somewhere in the bottom of infrared. Theoretically speaking, is it possible to emit visible light...