Electromagnetism Definition and 853 Threads

  1. L

    Why Does an Aluminium Rod Slow Down When a Current is Produced?

    Hi, I have a question concerning the attached diagram: The question which accompanied the diagram is: Why does the aluminium rod (the one that lies across the other two) slow down when a current is produced? The official answer is: "A current is produced in the rod which experiences a force...
  2. D

    How to Calculate Reflection Coefficient for Light at Air to Silver Interface?

    How does one calculate the reflection coefficient for light at an air to silver interface at optical frequencies (\omega = {4 *10^{15} s^{-1}}) given \mu_{I} = \mu_{T} = \mu_{0} , \sigma = {6 * 10^7 mhom^{-1}}
  3. H

    Explaining the Meaning of "Flux" in Electromagnetism

    I don't understand what is the meaning of "flux" .I just know it has some relation between eletromagnetism.Please explain what is flux to me.
  4. O

    Can Electromagnetism Affect Water Molecules and Change the Earth's Spin?

    This is a problem that's been puzzling me for a while now, so hopefully somebody knows the answers to some of these questions. Can an electromagnetic field cause water molecules to move? Can changes in the intensity or location of an intense electromagnetic field cause water molecules to, even...
  5. D

    How is electromagnetic force related to electromagnetic radiation?

    I'm very confused Electromagnetism confuses me. In a circuit the movement of electric charges creates a magnetic force. (the type of magnetic force that is associated with magnets) Why does the movement of electric charges produce a magnetic force? The combination of a electric field...
  6. D

    How Does Ion Momentum Relate to Magnetic Fields and Circular Motion?

    An ion with a change of 1.6*10^-19 enters a 0.075 T magnetic field. If the ion follows a circular path of radius 0.083m, what is the momentum of the ion? I tried manipulating Fc = Fmagnet into Momentum = QBr, but that didn't work... any ideas? Thanks!
  7. L

    Electromagnetism without any finger

    When I was a student, I remember that I disliked a lot these finger exercises. I soon realized that these were totally useless, and I solved everything without any finger rule. But since, I have forgotten how I did ! I only remember that I concentrated on currents, nothing else. Have some...
  8. S

    Electromagnetism: Moving Electrons & Magnetic Fields

    question on electromagnetism, moving electrons with respect to other electrons causes a field to be felt right? maybe if i skip to my example itl make sence... lets say you fire a bullet parallel to a wire. will the bullet feel a magnetic field, and if so, will it change its tragectory...
  9. T

    What are the classical Textbooks for quantum mechanics and electromagnetism?

    What are the "classical Textbooks" for quantum mechanics and electromagnetism? hi, I want to use my vacations to study quantum mechanics and eletromagnetism. Are there any "classical textbook" for these 2 subjects, like "Goldstein classical mechanics" for mechanics? Thanks, Twukwu.
  10. H

    Strong nuclear force vs. electromagnetism

    Hello, I'm wondering, which force is stronger, SNF or EM, how was it proven that specific force is stronger than the other, and are there actually any cases where the weaker force is actually the stronger one. Thanks for all the help
  11. B

    Explanation of the wording - Electromagnetism Question

    Could someone explain the wording (and possibly see if I'm going the right way about it) of this question to me. What is the current required in the windings of a long solenoid that has 1000 turns uniformly distributed over a length of 0.400m, o produce at the centre of the solenoid a...
  12. S

    What Is the Final Charge and Potential of the Inner Sphere?

    We have two hollow concentric conducting spheres which are intially isolated from their surroundings and each other. they are connected electrically, and the outer is connected to a potential source V, the connection between the spheres is then broken. finally the outer sphere is connected to...
  13. G

    Calculating Potential of a Hoop in Electromagnetism

    http://www.zen96175.zen.co.uk/question.GIF Hi everyone :-) This is my first post here! I have a question regarding electrostatics, in the picture above. I am not looking for the solution at all as this work will be assesed, I am just hoping that someone can verify/ poke me in the right...
  14. A

    Electromagnetism: Can anyone find the mistake?

    given: the electric field at a point on the axis a distance x from the plane of a ring is E = \frac {q*x} {4*pi*E0*(x^2+r^2)^{3/2}} where E0 is the permeability coefficient The charged ring is replaced by a circular sheet of charge of radius a a surface charge density sigma. The ring...
  15. K

    Some more electromagnetism questions (ac generators)

    A few more questions that i am stuck with: An AC generator has a coil area of 120cm². The coil has 100 turns. The generator produces a peak voltage of 29V when the coil is turning at 6000 revolutions per minute. Calculate the magnetic flux density (assumed uniform) required. The rate of...
  16. F

    Insight needed into electromagnetism problem

    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...
  17. B

    Describe forces on a test charge in electromagnetism

    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...
  18. S

    How to Solve Physics Electromagnetism Problems

    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...
  19. S

    How Do I Solve These Electromagnetism Multiple Choice Questions?

    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 =...
  20. E

    Electromagnetism and hydraulics

    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?
  21. F

    How Does Changing Magnetic Flux Induce EMF?

    Electromagnetism -- induced EMF Please help :) I'm just trying to grasp the whole ... induced EMF concept ... please, anyone?! Also ... breaking the field lines?
  22. V

    Working from electromagnetism to circuit theory

    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...
  23. H

    Question about electromagnetism and photons

    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...
  24. H

    Why Does a Charged Disk Generate a Non-Zero Electric Field at Its Center?

    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...
  25. Q

    Electromagnetism to deviate the path of an incoming bullet

    Hello,everyone I was thinking if electromagnetism could be used to deviate the path of an incoming bullet?
  26. N

    What are some useful websites for basic electromagnetism?

    hey all ... can i have sites 4 basic electromagnetism ? i would be so grateful to u ... cheers abc
  27. L

    Electromagnetism everyone's favorite

    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...
  28. G

    Electromagnetism homework question

    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...
  29. S

    Electromagnetism in my physics class

    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...
  30. B

    Questions concering magnets and electromagnetism

    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...
  31. R

    How Does a Conducting Loop's Size Affect EMF and Motion on an Inclined Plane?

    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...
  32. R

    Why does x1i =r1 -y1j in Lorentz electromagnetic force?

    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...
  33. K

    Is electromagnetism's symmetry affected by the composition of particles?

    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...
  34. L

    How Does Increasing Coil Turns Affect Electromagnetic Force in a Solenoid?

    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??
  35. D

    Simple electromagnetism question

    hi, i have a question, if you could help me, that'd be great: why does a smaller diameter coil result in a stronger electromagnet??
  36. K

    Higgs particle and electromagnetism

    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...
  37. S

    Question: Electromagnetism, Weak-force, Gravity, Strong Nuclear force ?

    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...
  38. K

    Where Can I Find Comprehensive Electromagnetism Notes Online?

    anyone who has some notes? or website where you can find em? i have tried google but with no luck need it! thanks guys!
  39. T

    What are the four equations that describe electromagnetism?

    What are the four equations that describe electromagnetism? (please leave an explanation to the letters)
  40. B

    Is Your DIY EMP Device Safe to Use?

    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...
  41. P

    Need help with electromagnetism problems?

    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...
  42. M

    Electromagnetism and the photon

    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...
  43. J

    Electromagnetism and the photon

    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?
  44. I

    Comparing Gravity and Electromagnetism

    Am interested in comparing gravity with electromagnetism. What are the differences in properties between the forces and how are they alike?
  45. K

    Can Moving Charges Create a Magnetic Field? A Discussion on Electromagnetism

    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...
  46. E

    Electromagnetism and renormaliztion

    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...
  47. T

    Electromagnetism Question: Electrons in Motion and Magnetic Fields Explained

    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...
  48. S

    Myron Evans O(3) Electromagnetism

    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...
  49. M

    How to Calculate Total Force on a Charge at the Center of Curvature?

    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...
  50. C

    I have studied electromagnetism in my Physics AP class

    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...
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