What is Electromagnetism: Definition and 838 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.
The problem (From Electromagnetism by Pollack and Stump, exercise 11.34)
A stationary charge of charge e and mass m encounters a electromagnetic wave with vector potential
\vec{A}=\vec{j}f(x-ct)
where
\vec{j}
is the unit vector in the y-direction. The scalar potential is zero...
I'm completely clueless with these statements. I watched a video on this, but all it said is that it was "complex" which didn't explain it much. If someone would possibly help me that would be great.. and appreciated! Thank you.
A. Describe the force "felt" by the test charge as it is...
I have 3 more physics electromagnetism problems, thanks again for the help (helped tremendously in the last unit for my test).
http://i2.photobucket.com/albums/y15/seiferseph/1.jpg
not sure what equation to use, i can solve for change in flux using the magnetic field and area, but not sure...
I have three multiple choice questions on electromagnetism that i have been unable to get. The answers are there, i just can't get them.
http://i2.photobucket.com/albums/y15/seiferseph/1.jpg
i can't find any equation to use that doesn't have more than two unknowns. I've tried Fb =...
hi, I built a crane using hydraulics to move the arm and using an electromagnet at the end of the arm to pick up and move metal objects... what other applications could use hydraulics and electromagnets?
Electromagnetism -- induced EMF
Please help :) I'm just trying to grasp the whole ... induced EMF concept ... please, anyone?! Also ... breaking the field lines?
Hi,
Are there ways to use/reduce electromagnetic theory to understand circuit theory better? ie use circuit theory as a special case of em theory? if so can you suggest books which do it this way?
basically my idea is to look at any circuit from the general point of view - using the physics of...
Sorry if this has been asked before, I searched but didn't find anything
What's the difference between EM radiation (photons) and EM fields? When an antenna is emitting a signal at X Hz, is it emitting photons with the frequency of X Hz or is it just making electrical and magnetical fields...
I have two questions.
The first concerns a charged disk. Consider the center of the surface of the charged disk, O. Mathematically, the value of E at O comes out to be a non-zero finite value. However i am having difficulty linking this with the physical sense. The disk can be thought to be...
Hi again guys. I've got a test charge place a certain distance away from a large flat uniformly charged non-conducting surface. I'm told what the force charge is from this distance. Then the test charge is moved, and I'm supposed to say what the force on the test charge is now. I tried doing it...
1. A simple generator has a 200-loop square coil 25.0cm on a side. How fast must it turn in a 0.550T field to produce a 120V peak output?
area=(0.25)^2
=6.25x10^-2
E=-N(BA)/t
t=-(300)(6.25x10^-2)(0-0.550T)/120V
t=8.6x10^-2 s
do you need to times it by 4 to get the time for one...
Well I was learning bits about Electromagnetism in my physics class and we were learning about transformers and thought it was kind of neat. I was just wondering why transformers use alterneting current and why power must be delivered at such high voltages across transmission lines? Also, how...
I am a bit confused about the concept of magnets. It is said that magnets attract opposites, and repel likes. Now does that refer to the material, or a magnet being attracted/repelled by another magnet?
Also...
If an electromagnetic apparatus is strong enough, will attract/pull just about...
A small conducting loop of mass m,radius r,resistance R is released from rest along a smooth inclined plane such that the plane of the loop is perpendicular to a magnetic field which varies along x-axis as B=B'(1+ax).here B' and a are constants.Find the speed of the ring as a function of time...
When going over my notes on the lorentz electromagnetic force in my physics 3 electromagnetism class got a bit puzzled by one statement that seems just to be taken for granted. Could anyone help me and tell me why x1i =r1 -y1j on page 5 on...
Quarks can't exist in isolation and the electric charge on quarks can't exist in isolation from the electric charges of other quarks either.The electric charge of leptons like the electron can exist in isolation.Isn't electromagnetism showing a kind of asymmetry here: symmetry could be restored...
An electric current passing through a coil of wire generated an electromagnetic effect.What effect does the number of turns of wire in a coil have on the size of the electromagnetic force?
What hypothesis can u form and how do you use the domain theory to support this??
The Higgs particle may never be found - Stephen Hawking doubts that it exists.
If mass isn't due to the Higgs, could it be caused by electromagnetism?
For example, if protons and electrons experience resistance to a change in their speeds from charged particles in the space around them,could a...
Great work has been done in the last while on the Four fundamental forces, but is there a fifth ?
Is there a Force Number 5 :confused: ?
I saw a discussion on this other website
http://www.thespacesite.com/community/index.php?showtopic=199
:surprise:
QUOTE:
the age of the...
I have constructed an EMP emitter device via some plans.. then i jacked it up to give it some more power. but, alas, i have scared myself. It is just a straight up electromagnet pulse generator, no microwaves or anything else (i am assuming, unless it generates them and i don't know yet...
OK first off I'd like to thank Warr for helping me with one problem
again thanks a lot
Okay now to business I have an ISU (Independent Study Unit) due this thursday and I'm pretty much all done, but it would be great if you guys could just look over it for any mistakes and or advices. ISU...
Theories in physics are often said to follow one another . This statement is both true and false . The development of a new theory does not necessarily invalidate the old theory , but often results in making the latter a particular or limiting case of the former . For instance Newtonian...
A simple question:
The force carrying particle for electromagnetism is the photon.
Is the photon traveling from the N-pole of a magnet different from the photon traveling from the S-pole of a magnet?
If not, how do the fields/photons know whether to attract or repel?
Hi,
I would like to clarify some points on electromagnetism. Most (if not all) of my teachers say that moving charges create a magnetic field. I would just like to know... relative to what? If two electrons move parallel to each other with the same velocity, would they show any magnetic...
i always have asked myself this question ..Feynmann and others got the nobel prize for quantizaying the electromagnetism..i have read about it and it seems it was a difficult task..but why not try this way .take the lagrangian of electromagnetism and take the hamiltonian to be H=E+B now we now...
for example, there is an electron moving at some speed in a straight line. a circular magnetic field is produce(just like electron moving in a line of wire). if there's a n observer moving along with the electron, then the electron will appear to be at rest with the observer. does it mean that...
Afther a bit of research i have at last found the right place to learn about the Miron Evans theory.
It is here:
http://www.aias.us/
From the many papers enumerated there i have foudn that these could be one of the most self-contained:
http://www.aias.us/Note05182003/finalwaveeqnms.pdf...
help! I need help with this homework problem.
--A line of positive charge is formed into a semicircle of radius R=60.0 cm. The charge per unit length along the semicircle is described by the expression [lamb]= [lamb]naught cos [the] . The total charge on the semicircle is 12.0...
Hi, I'm new here so I'm not sure how formal this should be:
I have studied electromagnetism in my Physics AP class at my high school but I have had a question at the back of my head. I don't have a very good physics teacher, and he was unable to explain this to me. My question is why, when...
help! I need help with this homework problem.
--A line of positive charge is formed into a semicircle of radius R=60.0 cm. The charge per unit length along the semicircle is described by the expression [lamb]= [lamb]naught cos [the] . The total charge on the semicircle is 12.0...
dear friends
there are some theoretical questions in my mind about electromagnetism
1) in RL circuits the induced emf starts to decrease from its maximum value to zero
and this is caused by the changes of flux
but why does the magnetic flux changes initially very rapidly and then starts to...
I can understand what the electric field vector E and the magnetic flux density vector B mean, but what exactly are the meanings of the two other vectors, the electric displacement vector D and the magnetic intensity vector H? What are their physical explanations?