What is Electromagnetic: Definition and 1000 Discussions

Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles. The electromagnetic force is carried by electromagnetic fields composed of electric fields and magnetic fields, and it is responsible for electromagnetic radiation such as light. It is one of the four fundamental interactions (commonly called forces) in nature, together with the strong interaction, the weak interaction, and gravitation. At high energy, the weak force and electromagnetic force are unified as a single electroweak force.

Electromagnetic phenomena are defined in terms of the electromagnetic force, sometimes called the Lorentz force, which includes both electricity and magnetism as different manifestations of the same phenomenon. The electromagnetic force plays a major role in determining the internal properties of most objects encountered in daily life. The electromagnetic attraction between atomic nuclei and their orbital electrons holds atoms together. Electromagnetic forces are responsible for the chemical bonds between atoms which create molecules, and intermolecular forces. The electromagnetic force governs all chemical processes, which arise from interactions between the electrons of neighboring atoms. Electromagnetism is very widely used in modern technology, and electromagnetic theory is the basis of electric power engineering and electronics including digital technology.
There are numerous mathematical descriptions of the electromagnetic field. Most prominently, Maxwell's equations describe how electric and magnetic fields are generated and altered by each other and by charges and currents.
The theoretical implications of electromagnetism, particularly the establishment of the speed of light based on properties of the "medium" of propagation (permeability and permittivity), led to the development of special relativity by Albert Einstein in 1905.

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  1. M

    Electromagnetic wave complex wave function

    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}
  2. S

    A question on Electromagnetic theory

    Hi, In EM theory to derive the 'wave equation for electric field in a conducting medium' we make ρfree to be zero, but we still use σ to be nonzero. My question is why we are doing this ? σ denotes the conductivity of the material and a material can not conduct if it has no free carriers...
  3. F

    Electromagnetic waves interacting within space

    Hello everyone. I have a question about waves and how they interact in certain settings. 1.) What happens when two EM waves (of different frequencies and amplitudes) arrive at the same space at the same time, and are traveling 45 degrees to one another? Do their trajectories, amplitudes, and...
  4. D

    Electromagnetic induction (production of emf)

    Homework Statement the ans is C for this question. i really have no idea , van someone explain please? Homework Equations The Attempt at a Solution
  5. D

    Electromagnetic induction graph of E versus I

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  6. O

    Calculating Electromagnetic Force at 0 Distance?

    If you'll allow me to disregard the effects of Strong Interaction, how would I calculate the Electromagnetic Force between two oppositely charged point particles that are in contact with one another? Let's assume two particles with opposite Elementary Charges: 1.60218E-19 and -1.60218E-19 and...
  7. T

    Electromagnetic wave in two media

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  8. TESL@

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  9. M

    Quantization of the Electromagnetic Field

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  10. Luck0

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  11. W

    Electromagnetic damping logarithmic decrement task

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  12. W

    Help understanding the electromagnetic radiation; mainly near field.

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  13. W

    How to Determine the Magnetic Field B Using Forces F1, F2, and F3 on a Charge?

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  14. B

    How much of the universe is in the form of electromagnetic radiation?

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  15. P

    Electromagnetic Induction Problem

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  16. L

    Electric and magnetic fields VS electromagnetic waves

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  17. kmm

    Electromagnetic waves with regard to photons

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  18. G

    Manipulation of Electromagnetic fields using curls clarification

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  19. V

    Need help on electromagnetic poles and induced current

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  20. F

    How Do Charge Distributions Affect a Spherical Dielectric Shell?

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  21. K

    Classical and quantum electromagnetic field

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  22. D

    Electromagnetic force between Parallel Currents

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  23. PeteyCoco

    Electromagnetic wave emission after source vanishes

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  24. E

    Can Copper Coils and Iron Pipes Create Electromagnetic Propulsion?

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  25. D

    Electromagnetic Lagrangian

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  26. F

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  27. P

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  28. J

    Electromagnetism Electromagnetic fields

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  29. E

    Gravitational Attraction, Electromagnetic Radiation and Dark Matter

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  30. S

    Bragg's law and the distribution of electromagnetic energy.

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  31. W

    Is Max Planck law true for all electromagnetic waves?

    Is it true that the energy in electromagnetic waves can only be released in "packets" of energy? Or is this only the case for a system where a standing wave change from one mode to another which results in sending out an electromagnetic wave (photon). In other words if I ride on my bike...
  32. M

    Stress-energy tensor for electromagnetic field with interaction term

    First of all, I'm not sure if this thread belongs here or at the "Special & General Relativity" sub-forum, if I posted at the wrong place please move it. Homework Statement I encountered this problem working in my master's degree. I need to find the stress-energy tensor of the following...
  33. D

    Electromagnetic waves vs the laws

    Does the law of the conservation of energy apply to the light in our universe? If yes, is our universe a closed system? If no, is our universe losing energy?
  34. P

    Physics 2: Electromagnetic Theory (Amperè's Law, Biot-Savart, etc)

    Homework Statement First off: these are not homework problems technically, I'm doing these for my own benefit...they're not being graded or collected. Just trying to study for my final. Problem 1 A thin spherical, conducting metal shell has a radius of 15.0cm. A positive charge of 1.30µC...
  35. F

    Charged particle movement in arbitrary electromagnetic field

    Hello there! This is my first post here, hopefully I am not posting in the wrong place. Also, I am an engineer and have not used this stuff for years, so please be patient with me, I am pretty sure that my question is stupid :-) I would like to develop a simulation code for charged particles...
  36. H

    Electromagnetic energy of a long wire

    When we have a current in a long wire, what is the kind of total energy of the system? We do have an electric field inside the wire and a magnetic field outside it. I think the electric field has an energy, say E, and it is only this energy which appears also as magnetic energy and we don't have...
  37. F

    Calculating Electromagnetic Force on a Moving Wire

    Homework Statement A wire of length L=20cm travels with an acceleration a=0.002m/s2 perpendicular to the Earth's magnetic field (B=20μT). Considering that the wire starts from rest, calculate the value of the emf (electromagnetic force) when an hour has gone by. Homework Equations My...
  38. B

    Designing an Electromagnetic Toy: How to Improvise with Limited Resources

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  39. M

    Large Electromagnetic Jig Project

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  40. B

    Can a Race Car with Magnetic Wheels be Designed for a Final Project?

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  41. C

    What Causes Eddy Currents in a Copper Tube?

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  42. R

    Normal Force: A summation of electromagnetic forces?

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  43. H

    Electromagnetic radiation and perturbation

    Why do we often treat the electromagnetic radiation effects on Hamiltonian of a matter as a perturbation? In the other words, why the effects of radiation is so little that is treated as a perturbation?
  44. P

    Universal electromagnetic field formula

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  45. B

    Chemical energy to electromagnetic energy transer

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  46. B

    What is the direction and explanation of electromagnetic radiation?

    This isn't really a homework question, but I felt it was better suited here than in General Physics. I'm looking for more of a general explanation than anything. I was able to do my homework for this section on my own (mostly), but I feel like I still really have no idea what is actually going...
  47. dwn

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  48. W

    Sound Wave, Microphone and Electromagnetic Induction

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  49. S

    Can Parallel Charged Particles Maintain Their Speed in Space?

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  50. S

    Polarization of Electromagnetic Wave and Faraday's Law of Induction

    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...
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