Electricity and magnetism Definition and 215 Threads

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. Astronuc

    What Does the Physics 122 Course by Frank L. Wolfs Cover?

    Physics 122 Course by Frank L. Wolfs (homepage - http://teacher.nsrl.rochester.edu/) Department of Physics and Astronomy University of Rochester http://teacher.nsrl.rochester.edu/phy122/Phy122HomePage.html#info Course notes [see post #4 for revised link]
  2. M

    HW question: electricity and magnetism

    The potential is constant throughout a given region of space. Which of the following statements is true? Be sure you can justify your answer. 1. The electric field is zero in this region. 2. The electric field may have places where it is zero, and places where it is...
  3. M

    How Do You Calculate the Electrostatic Force Between Two Charged Lines?

    Electricity and Magnetism urgent!pls! An infinite long line of charge of constant charge density a is located near the line AB which carries uniform charges with charge density b. Suppose both two lines are in the same plane, calculate the electrostatic force exerted on the line AB. i don't...
  4. M

    What Are the Electric Field Components at the Center of a Charged Square?

    Electricity and Magnetism urgent!help! 11. Electric charge is distributed uniformly along each side of a square. Each side of the square has length a. Two adjacent sides have positive charge with total charge +Q on each. (i) If the other two sides have negative charge with total charge –Q on...
  5. G

    How Is EMF Induced in a Falling Metal Rod Affected by Earth's Magnetic Field?

    1) A horizontal metal rod of 1.5m long is aligned in and East-West direction and dropped from rest from the top of a high building. Calculate the e.m.f. induced across the falling rod 2.5s after release. The horizontal component of Earths magnetic field is 2x10^5 T. Surely you need the area...
  6. C

    A few questions about electricity and magnetism

    Hi, I'm new to this site. Anyway, I am studying for the MCAT right now and the physical science review that I have been doing has gone pretty well, I just have a few questions about comparisons that can be made between movement of electrons and movement of solid objects. 1) What is the...
  7. A

    Electricity and Magnetism Problem

    1. Is Ampère's law (\nabla \times \mathbf{B} = \mu _0 \mathbf{J}) consistent with the general rule that divergence-of-curl is always zero? Show that Ampère's law cannot be valid, in general, outside magnetostatics. Is there any such "defect" in the other three Maxwell equations? I'm not...
  8. B

    Electricity and magnetism question

    I'm having trouble starting this problem... I'm pretty sure I'll be able to figure it out if I can just get past the first question. I scanned the sheet because I'm lazy and I thought that you'd be able to understand the problem better that way anyways. So if someone could just point me in...
  9. J

    Understanding Charge, Voltage, and Circuit Analysis

    Hi my grade 11 physics class is on its final unit (Electricity and Magnetism) and I am a little lost... So far we are doing Charge and Voltage (we learned the formulas)... and we're expected to know that circuit diagram stuff and Ohm's Law? lol a bunch of stuff we were suppose to learn in grade...
  10. M

    How Can I Prepare for a Class in Electricity and Magnetism?

    Hello, I was wondering if you guys know any websites/ free books/ any other ressource about physics electricity and magnetism, since this is my next class and I want to try to read about it before starting. I have download an e-book from the sticky, but I'd like other sources. feel free to...
  11. S

    Electricity and Magnetism

    I have a huge problem to work out.. but first, i can't find the equations for (1) electrostatic potential of the center of a square (a charged particle at each vertice) and (2) the magnitude of electric field at the center of the same square. These are both questions to two...
  12. S

    Help questions on electricity and magnetism

    help! questions on electricity and magnetism 1. What is the frequency of the magnetic filed if it is know to be perpendicular to the electric field. The magnetic field is 0.00178T and the electric field is 8000V/m. 2. I just need the angle for this one. At a certain location, the...
  13. D

    Are electricity and magnetism more alike or different?

    ive been doing some thinking to a question brought up by my advanced physics teacher...i can't really back up any of my responses though...any help on whether electricity and magnetism are more alike or different?
  14. R

    Electricity and Magnetism problem

    Not even sure where to begin with this question: Estimate the magnitude of the potential difference produced by the motion of a conductor in the Earth's magnetic field for which B is 4.3x10^-5T and the angle of dip (the angle it makes with the horizontal) is 60 degrees. Take as an example a...
  15. D

    Electricity and Magnetism for Engineers Texts

    I just finished a Physics course in Electricity and Magnetism and never worked so hard for a 'B' in a class. I'd really like to go over the material once more to get a better handle on it during our break. I was thinking that a fresh approach with a different text might help, so I was hoping I...
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