E&m Definition and 242 Threads

  1. theoryboi

    Admissions Can I get away with retaking E&M, even if I got a B?

    I am in my first semester of physics after transferring from engineering, and I arrogantly took E&M instead of the recommended courses, and I am on track to get a B- or a B in the class. I plan to apply to PhD programs in a few years and even with this grade I don't thing a 3.7 or 3.8 is...
  2. Wmdajt

    E&M: Gauss' Law Surface Charge Density

    In this question I need to find the inner and outer charge density of the shell I did part A just fine, I used the formula for an electric field due to a line charge, but parts B and C is what's really confusing me. I'm not really sure how to go about it, I placed a spherical gaussian surface...
  3. notgoodatphysics

    Classical Recommendations for 1st year E&M practice/exercises

    Currently in 1st year (UK) going through E&M right now, the recommended textbook is University Physics by S&Z. Recently had my-mid term test and got 40%. The problem is I’m overestimating my ability as the exercises in UP are not challenging at all, the majority of them are just plugging in...
  4. F

    A Puzzled about Section 3.12 of Jackson's E&M book

    Hi wizards, I'm working through Jackson's book on E&M (3rd edition) and got stuck in section 3.12 on expansions of Green functions. I have three questions regarding section 3.12: First, why is Jackson trying to find a Green function that satisfies equation 3.156? To my beginner mind, it...
  5. MidgetDwarf

    Classical New E&M Text by Wald - Princeton Press 30% Off

    [Mentor Note -- this thread about Wald's text split off from this thread start about book discounts:] https://www.physicsforums.com/threads/princeton-press-30-till-july-31-2022.1010897/
  6. S

    Intro Physics Books for high school physics E&M [No integrals]

    Can you recommend introductory physics book for high school that contains E & M ? It should not have any integrals.
  7. Passers_by

    Classical The first book of E&M is for self-study

    Can Classical Electromagnetism by Jerrold Franklin replace Griffith's for self-study? The book is now in its second edition.
  8. J

    Electric Potential of point outside cylinder

    Edit: Below is my work but i believe i have chosen the wrong values of the separation vector in the s direction. Any ideas as to what it should be?
  9. S

    Find the angular acceleration of two reflectors attached to a rod

    Okay so I actually have the answer because my teacher basically just gave it to me, but I would really like to know why I was even wrong in the first place. Here's my steps: 1. Knowing the momentum transfer per unit area is described by: 1/A dp/dt = S/c. I can begin by relating some known...
  10. F

    What happens to σ (conductivity) when the permitivity is negative?

    We are using the textbook by Jin, "Theory and Comutation of Electromagnetic Fields". In the section on metamaterialshe derives the dispersion relationship. He shows that when ε'= -ε & μ' = μ then the dispersion equation γ =\sqrt{jωμ( jωε +σ )} = α + jβ goes to γ = α = ω \sqrt{μ'ε'}...
  11. Hamiltonian

    Particle Electrostatics/dynamics and E&M, where's a good place to start?

    so I recently finished the basics of classical mechanics and decided to start with electrostatics/dynamics, I started with Griffiths but found pretty challenging should I just persist and continue with it or maybe go through the Feynman lectures(vol2) or electricity and magnetism by Purcell and...
  12. S

    B The nature of orthogonal oscillations (extending E&M)

    Classical electromagnetic propagation evokes an electric field at right angles to a magnetic field. Does this complementary directionality have a simpler basis in QED? Are there any examples of an orthogonal component in other fundamental interactions? Thanks.
  13. K

    E&M: Field of a Wire with non-uniform current

    Summary:: Not sure if my solution to a magnetostatics problem is correct [Mentor Note -- thread moved from the technical forums, so no Homework Template is shown] I was trying to solve problem 2 from...
  14. Mondayman

    Classical Supplement to Griffiths E&M/Prep for Graduate E&M

    Hi folks, I'm currently working through Griffith's E&M text for school. It is my favorite subject and I am hoping to find another textbook or problem book on electrodynamics or electromagnetics. I was hoping for something at the level of Griffiths or slightly above, something that'll prepare me...
  15. Blakely42

    Learning Nothing from my E&M Course

    Summary:: Griffiths' Electrodynamics Text is Worthless for Teaching It seems like Griffiths just makes things up as he goes along. There's no reasoning. Sometimes he does things one way, sometimes another. Solutions are never really explained, whether I look up homework solutions online or...
  16. vis viva

    E&M fields simulated and visualized in COMSOL, is that how they 'look' IRL?

    Hi I made a simulation (comsol) of a piece of aluminum wire (r=1mm h=10mm) excited by 1A DC inside a sphere (r=10mm) of air. Here are the 3D plots: Since I ever only have 'seen' E&M fields depicted in textbooks and never in real life, I'm a bit surprised by the simulation result, I would at...
  17. S

    [E&M] Question on the Image charge method of a grounding sphere

    So I was reading Jackson's discussion on Image charge method of a grounding sphere. He first assumed an image charge q inside Sphere with radius a, so the potential for real change and image charge is . The by set potential equal to 0 at x=a, he solved q' and y' Then he can get potential...
  18. J

    Classical Using Zangwill for grad E&M instead of Jackson?

    I'm starting a physics PhD program in the fall. I asked a current student what textbooks are used, and was surprised that the textbook for electrodynamics was not Jackson. I got the impression that Jackson was the standard. E.g., My undergraduate institution (a top physics school) uses Jackson...
  19. I

    Jackson E&M: Power loss in waveguides for TE & TM modes

    Hi. I'm having trouble with calculating (8.59) from (8.58) (## \vec H_{//} ## is simply ## \vec H ## in Jackson, but that shouldn't matter.) in Jackson. Specifically I think I'm not sure about parallel component of H field here. For example, shouldn't I have two terms for the...
  20. S

    Textbook says V=E/w but units don't match

    In my textbook, it is talking about the Hall Effect on a flat conductor with width w carrying a current i in a uniform magnetic field perpendicular to the plane of the strip. It says that this will create a potential difference of V=E/w where E is the induces electric field from the electrons...
  21. A

    Classical Searching for Challenging Physics Problems: E&M, Optics, Thermo & Mechanics

    Hi! As the title suggests, I am searching for some good problem books with really challenging problems for classical physics, more precisely on the topics of electricity and elecromagnetism, geometrical optics and wave optics, thermodynamics and analytical mechanics. When I say challenging I...
  22. J

    My E&M textbook claims that fields are a form of matter

    I'm studying out of Classical Electrodynamics by Ohanian and in chapter 2 (Electrostatics) he makes the following claim while discussing the electric field: I'm a little confused by this, and I can't seem to find any sources that share this view. I'm even more confused because in the...
  23. B

    Polarizibility, Electric Field & Force

    Homework Statement A neutral atom with known polarizability α is located at the origin. A point charge Q is situated on the y-axis a large distance d from the atom. (The atom therefore becomes polarized due to the electric field of the point charge.) (a) Find the electric field due to the atom...
  24. starstruck_

    Studying Anyone who struggled to understand E&M at first, any tips?

    hey! It's me again. For anyone who has been answering my questions // looking at my posts (thank you), you've probably already been aware that I never touched electricity in high school - the last time I did electricity and magnetism was in grade 11 and I couldn't solve a single circuit...
  25. Gene Naden

    Classical Looking for a textbook of undergrad E&M, for Physics Forum Help that I give

    I sometimes post answers to threads people post about E&M. Unfortunately, my Masters in physics was 40 years ago and I am a little rusty. I am looking for something that will help me answer people's questions. The level of math can be fairly sophisticated as I have brushed up a bit.
  26. N

    How Do You Apply the Divergence Theorem to a Vector Field in a Unit Cube?

    Homework Statement Griffiths Introduction to Electrodynamics 4th Edition Example 1.10 Check the divergence theorem using the function: v = y^2 (i) + (2xy + z^2) (j) + (2yz) (k) and a unit cube at the origin. Homework Equations (closed)∫v⋅da = ∫∇⋅vdV The flux of vector v at the boundary of the...
  27. dreens

    I Can the Electromagnetic Force be Explained by Curving Spacetime?

    So General Relativity explains the force of gravity as mass/energy induced curvature of spacetime. This correctly predicts gravitational time distortion, nonlinear geodesics and gravitational lensing, the anomalous precession of planetary orbits, the schwarzchild metric, and so on. Could the...
  28. CrunchBerries

    Classical Is Purcell's E&M Book Recommended for Studying Physics with Calc 3?

    I have already taken the following online courses: - Physics 1 (calc based, mechanics) - Linear Algebra - Calculus 1 - Calculus 2 - Electronics technician by trade Next semester I will be taking multi variable calculus, in preparation for a brick and mortar Canadian university for fall of 2018...
  29. astrocytosis

    Induced current in a loop of wire when straight wire is cut

    Homework Statement A square loop, side a, resistance R, lies a distance s from an infinite straight wire that carries current I (pointing to the right). Now someone cuts the wire, so I drops to zero. In what direction does the induced current in the square loop flow, and what total charge...
  30. P

    How does the differential form of Faraday's law relate to induced current?

    Homework Statement I'm in a class where we have to essentially learn E&M ourselves and I'm challenged by Maxwells equations. I'm studying out of Purcell's E&M. The differential form of Faradays law for Maxwells equations is curl E = -∂B/∂t Im having trouble interpreting what to make of this...
  31. M

    E&M separation of variables and Fourier

    Homework Statement Boundary conditions are i) V=0 when y=0 ii) V=0 when y=a iii) V=V0(y) when x=0 iv) V=0 when x app infinity. I understand and follow this problem (separating vars and eliminated constants) until the potential is found to be V(x,y) = Ce^(-kx)*sin(ky) Condition ii...
  32. E

    Programs Vector calculus and E&M physics as a engineering major?

    I am an engineering major at Los Angeles Pierce community college. I have been for the last years working 40 hours a week in order to sustain and put myself through community college. After I transfer, I don't plan on working. Now, each semester due to my work schedule and life happening, I can...
  33. M

    Courses Mechanics / E&M / Multivariable Calc / Diff EQ Self Study

    Hello Physics Forums! I'm in a little bit of an interesting situation. I've completed the classes offered at my school, but have been told that if I can directed-study these four courses they will provide me with a credit bearing exam for college undergraduate credit. Do you have any...
  34. J

    Estimating Electromagnetic Radiation from a Cellular Phone

    Hello all, I have a problem with a typical style of problem I seem to always struggle with. Just to clear this up, I am studying for my comprehensive exams later this summer. So I am going through past problems to bone up on the last two years of grad school. At which point I came across this...
  35. TBert

    I What Is the Physics Behind Particle Traveling Over Voltage?

    A friend of mine showed me a diagram like this: I think they said it was describing the probability of finding a charged particle in a certain place when traveling over a voltage. They said that if the particle doesn't have enough energy to make it across then it gets stuck at the beginning...
  36. Spinnor

    I Approximate a plane E&M wave with this large sum....

    I would like to approximate a plane electromagnetic wave with a very large sum of the following. Let an infinite line, say the z axis, have a electric polarization on that line and perpendicular to that line, say the x direction to be specific given by, P(z,t) = pcos(kz-ωt). The polarization...
  37. C

    [E&M] Sliding Conductor & Magnetic Field

    Hello, Please consider this diagram: From the diagram, we can see there are two forces. One: The Lorentz Force (qvB). Using the RHR, we can see that there is a force pushing north (up) to cause the separation of charges in the sliding conductor to establish the current in the loop. Two...
  38. Spinnor

    B Photon, string theory string, E&M field

    Is it possible to associate electric and magnetic fields with the vibrating string that is thought to represent a photon in string theory? Thanks!
  39. D

    Courses Can I catch up on physics 1 & 2 in 3 months?

    So I am currently an ME major at CC. I am probably going to transfer to a university to study physics next fall but there is one problem... I took physics 1 & 2 at a community college that is very heavily focused on their engineering program. Because of this, I only learned things in physics 1...
  40. I

    Suggestions for practice problems in E&M

    Hey all, I am working my way through a couple of emag books (Griffiths, Jackson, and Schwinger) and I was wondering if any of y'all have suggestions for problems that you thought were particularly physically insightful or useful. Cheers, IR
  41. hilbert2

    A Spectral intensities from E&M fields

    A question about the relation of light intensities to the actual time-dependent EM field: Suppose I have a system where the functions ##\mathbb{E}(\mathbf{r},t)## and ##\mathbb{B}(\mathbf{r},t)## (time and position dependent electric and magnetic fields) are known. I would like to have an...
  42. yeshuamo

    Courses Is Grad-Level E&M a Risk for a Serious Physics Student?

    I am an undergraduate with 3 more semesters left and with the majority of my physics core complete, except for quantum theory. I'd like to give my best effort to entering a top graduate school, but I got B marks in E&M I and Classical Mechanics. This semester was a turnaround, with straight A's...
  43. Z

    Magnetic field in an offset hole in a conductor cylinder

    Homework Statement A long (infinite) wire (cylindrical conductor of radius R, whose axis coincides with the z axis carries a uniformly distributed current I in the +z direction. A cylindrical hole is drilled out of the conductor, parallel to the z axis, (see figure above for geometry). The...
  44. FallenApple

    Where can I find advanced E&M videos on the level of Griffiths?

    I'm looking for good videos on advanced E&M on the level of Griffiths. A lecturer in the style of Walter Lewin or Shankar is what I'm used to. Someone with strong emphasis on concepts &/or theory. Any recommendations?
  45. madmax87

    A I need to understand the following E&M points

    dear all i need the help in understanding the following points: 1- In E&M, what is happening (physically) at anomalous absorption?, and how is this explained by the form of permittivity (real and imaginary parts)? 2- why did the "electric displacement" call that way?
  46. C

    Postion vs time graph without time or initial speed?

    Homework Statement Consider the system shown to the right. Particles 1 and 2 are fixed in place while particle three is placed at the location shown and released. Let’s look at the mechanics of q3, which has a mass of 3.00 X 10-5 kg. What will be the net force on q3?What will be q3’s...
  47. CentrifugalKing

    Circular Wave Fronts Emitted by Two Wave Sources

    Homework Statement https://session.masteringphysics.com/problemAsset/1383558/3/21.EX26.jpg Make a table with rows labeled P, Q, and R and columns labeled r1, r2, Δr, and C/D. Fill in the table for points P, Q, and R, giving the distances as multiples of λ and indicating, with a C or a D...
  48. PhotonSSBM

    Studying Picking up necessary Classical Mechanics and E&M for GR

    My professor is mentoring me through learning GR over the next year with the goal of doing research with me in the long term in the field. I need to pick up a few things along the way. The summer is going to be spent mostly picking up the necessary material for jumping into Carroll's book, and...
  49. R

    Magnitude and Direction of induced voltage

    Homework Statement Hey everyone I have a physics e&m question: [/B] http://blob:https%3A//www.physicsforums.com/aa779f37-be23-43d7-a888-d70263a3854b Homework EquationsThe Attempt at a Solution I took the derivative to find the magnitude of the induced voltage. (do I need to add a constant...
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