E&m Definition and 242 Threads

Homework Statement I'd like to preface this by saying I'm not doing this as "homework" per se, but rather reviewing my physics coursework from my undergraduate years, prepping for grad school. So w/ that brief introduction, I'm working through Problem 3.19 in Purcell's famous textbook on...

The magnetic field inm the gap of the toroidal permanent magnet is 0.50 T. The length of the magnetic circuit is 20 cm and that of the gap is 1.0 cm. what are the magnitudes of i) B in the material ii) H in the gap iii) H in the material iv) M in the material The Attempt at a Solution...

Prove that in a magnetic mirror the flux encircled by the orbit of the particles is conserved when the magnetic field varies. How do you do this? i have no idea how to approach/start this!

This problem is finding the potential difference between the vertex (a) and the center of the top (b), for a cone with height and radius H. Can this problem be done by: finding the potential at (b) using a flat disc and then finding the potential at (a) using the surface area of a cone (without...

E&M Electric Fields (Harmonic Motion?) This problem comes out of "Physics (for scientists and engineers w/ modern physics) Volume 2 7th Edition" by Serway/Jewett Review Problem Two identical particles, each having charge +q, are fixed in space and separated by a distance d. A third particle...

is it a plausible thing? I'm sure it's possible because almost anything is possible, the question is it wise? an example of my hesitation to study something before it's prerequisites is that i don't want to study QM before studying hamiltonian and lagranian mechanics. should i be worried about...

The method of images exploits the fact any linear combination of solutions to a differential equation is also a solution, and the fields and potentials from a point source satisfy all relevant diff eq's, assuming the boundary conditions are met. However, a scalar multiple of any solution is...

Hello Physics Forum people! :) Homework Statement The three regions in the figure below contain perfect dialectrics. For a wave in medium 1, incident normally upon the boundary at z = -d, what combination of \epsilon_{r2} and d produces no reflection? Express your answers in terms of...

Do you need to be very good at introductory mechanics to do well in introductory E&M? Or can you still do good in E&M (get an A) if you are not very good at introductory mechanics? To prepare for intro E&M should I do (A) review intro mechanics or (B) start studying E&M from a book like serway...

I'm trying to solve a problem in E&M, and I got an equation which depends on p and q, which I can solve provided I can write sinh(\sqrt{p^2 + k^2} \pi) as a product of a function of p, with a function of k. If I can do that, I can solve the problem, but I don't know how to do that part (or if...

Homework Statement In the case of total internal reflection, show that the average rate of energy transport across the boundary is zero. Homework Equations None Provided The Attempt at a Solution All that I have come to is that I should use some form of the following method to find...

E&M: Using Laplace's Equation to solve for a conducting "slit" Homework Statement The set up is as follows: You have a conductor at potential 0 along the y-axis at x=0. You have another conductor at potential V=Vo running along the x-axis at y=0. You have a third conductor at potential V=Vo...

Hello, I am in electricity and magnetism. I have a question about a homework problem. A 1000-turn loop (radius = 0.034 m) of wire is connected to a (20 ohm) resistor as shown in the figure. A magnetic field is directed perpendicular to the plane of the loop. The field points into the paper...

I'm looking to test out of my schools Electricity and Optics class (so E&M with optics really). I was wondering what a good book would be to be able to teach myself this topic well. I'm interested in it, so I'm not just going for the whole "take the test, be done with it" sort of thing. I...

So our latest E&M homework assignment out of griffiths has a bit of a twist. For all of the answers that we get we have to show that they seem reasonable. I know for instance with a charged solid sphere of radius R you could take R<<r where r is the distance away from the sphere and see that it...

Hi, all, My question is if I have two plane E&M wave traveling in the x-z plane, and they are polarized along the y direction, and I know that there is an angle theta between their propagation vectors, how do I set up the equations to get the intereference pattern in the z direction? I...

Some years ago I helped a talented young boy do a project for his elementary school science fair. He wanted to build an electric motor and “see how fast it would go with different batteries.” After building the usual wobbly paper-clip-and-toothpick type motor that needed careful jiggling to get...

Hi, This problem has me stumped and I keep thinking that I'm missing something simple. The question gives us a simple model for modelling a microwave. We consider a plane wave traveling through an object in the microwave (in the z direction), with no reflection. So, the general form should be...

In fact, This is a question I caucalated in HW. But I still dun understand the answer. Any have the idea about this question? The problem is in this link http://web.mit.edu/8.07/www/probsets/PS6s.pdf The problem No.2

Next semester I'm taking Intro to Physics II and Calculus II concurrently. Calc II is a co-requisite for Physics II, but in Physics I I've found that sometimes the teacher presumes knowledge not yet taught in Calc I (co-requisite for physics I). I was wondering if there were any topics in Calc...

Hi, I was wondering if anyone knew of any online lectures on E&M at the level of Griffith's "Introduction to Electrodynamics"? Either video or audio would be fine... I'm plowing through this book on my own, and could use a little assistance. (I know about the lectures for 18.02 at MIT OCW, but...

A point charge (q, mass m) is released from rest at a distance d from a grouned infinite conducting plane. How long does it take to hit the plane? Answer pi*(d/q)*sqrt(2pi*eps m d) This problem seemed easy to me at very, but it leads to a second order nonlinear equation m\frac{d^2 z}{dt^2}...

I'm given this: A vector field is given in cylindrical coordinates as: F=(A)(s)(PhiHat) + (B)(z)(zhat) Where A and B are constants. Could F be an electrostatic field ? Why or why not ? I kind of feel stupid asking this because I feel like I should know, but, I'm currently braindead...

Hi, I've been trying to figure out this problem for a while now and I could use some help. The problem reads "An electron and proton attract each other with a 1/r^2 electric force, just like the gravitational force. Suppose that an electron moves in a circular orbit about a proton. If the...

Does anyone have any references or pointers to the complete electromagnetic field of a "Gaussian Beam"? By Gaussian, I mean that for a beam propagating in the z direction, a cross-section of the beam in the x-yplane has |E| = k exp( -(x^2+y^2)/w^2 ) see for instance...

Hello All, I understand this is more of a question for electrical engineers however I have received only baffling replies from electrical engineers so I was hoping a physicist, or someone a little better versed in E&M than I am, could assist in finding an answer to this question. Long...

Dunno who already knows... but a recap... I thought i'd failed physics... i though my final exam wouldn't even matter... i decided i'd retake the class, and not take the final... emailed my prof finally... he decides to give me a second chance... if i can get a C on the final... he'll pass me...

So, I'm pretty sure i failed E&m this semester. I hated the class, so i was doing the minimum to get by. unfortunately, i didn't really account for the retarded way my professor grades, and so while i only wanted to just barely passed, i failed... i very very much failed. It isn't official or...

Hi, I need help on the following question: Suppose a point charge q is constrained to move along the x-axis. Show that the fields at points on the axis to the RIGHT of the charge are given by \vec{E} = \frac{q}{4\pi\epsilon_0}\frac{1}{r^2}(\frac{c+v}{c-v})\hat{x} and \vec{B} = 0 What...

There are two things related to using oscilloscopes that I am a bit fuzzy on for a practical lab exam I will take tomorrow morning: 1) Use the oscilloscope to determine the frequency of the square wave between terminals B and C of the test box. ( We will press and hold down the button on...

1. We have a grounded infinite conducting plane lying in the xy plane and a point charge held a distance d above it. Griffiths says that this implies that i) V = 0 at z = 0 (since the conducting plane is grounded ii) V --> 0 far from the charge (that is, for x² + y² + z² >> d²) My...

So i have a midterm tomorrow in E&M and I'm not well prepared at all. The whole class is pretty much already prepared to fail... so I'm not alone in that at least. Basically, i have one more day (tomorrow) to study, so i best make the best of it. We get to bring index card "cheat sheets" that...

hi everyone can anyone explain to me or show me some site that explain Maxwell's equation in simple language... i have been reading most of my teacher's books but i still don't get it. (my teacher doesn't want to teach me... sigh) and where can i find a good introduction of E&M? thx a lot!

What are the best books to master E&M !? I've been looking around for extra material, another other then knight's next which we're using, but i can't settle on what text to buy. They’re so expensive too. :eek: Here are the links for the two I hear most about. This one covers way more...

It is my view that the road to a unified quantum theory of gravity and electromagnetism begins with unifying GR and E&M classically (i.e. a non quantum mechanical formulation). They show so may similarities that they may be more closely related than we think.

Hey everyone, This term I'm enrolled in E&M which is a subject I've never formally learned anything in but I've loved for years and gained a lot of practical knowledge in (I'm a Ham radio junkie). Now I'm one week into the course and I really like it but there's one problem that needs to be...

Does anyone know of references to attempts at explaining electricity and magnetism via a geometrical technique similar to how general relativity explains gravity? thanks.

I want to find another book to study E&M. The book I have is university physics by sears/zemanski 11th ed. I think the book is ok but not great. Anyone know of any good E&M book that I can use to study this? I don't want to do problems, so I don't care if the problems in the back are terrible or...

I'm taking a first semester electricity and magnetism class and my teacher is quite a bit more rigorous than the textbook that he requires (Physics V2 by Halliday, Resnick, and Krane), so, in other words, my textbook is insufficient for the class. Does anyone have any recommended outside...

Need help verifying E&M Multiple Choice (True/false) (Referring to a diagram that is an ideal battery with wires connecting the positive and negative ends to a resistor in the form of a lightbulb of 30 ohm resistance creating a circuit). I'm also fairly sure the wires resistances are 0.1 ohm...

My problem has force decreasing with F=(1/r^2)r, where F is a vecotr and r is unit vector. i need to find a).work done in moving from a point at r=sqrt(2) to a point at r=2*sqrt(2) by a direct radial path and (b) by a path from (1,1)-->(2,1)-->(2,2). Compare my answers. a)I did direct radial...

I've just completed my first year of physics. I got A's in the first two quarters, but E&M gave me a hearty asskicking. Is electromagnetism supposed to be this difficult? Is it an aberration or the norm for physics classes from now on?