E&m Definition and 242 Threads

Apologies if this is being posted in the wrong section! this is just a side thought I came across, it is not HW. In learning about magnetism, I know that a changing current in a wire creates a magnetic field. So why are wires in our homes/ anything with wires close together not constantly...

Homework Statement Homework Equations Provided in the questions I believe. Here's the triangle from question two. The Attempt at a Solution QUESTION SET 1 TOP OF PICTURE A.) I didn't know how to just "guess" what the constant should be so I actually worked it out. I found the constant...

Homework Statement [/B] A very thin plastic ring (radius R) has a constant linear charge density, and total charge Q. The ring spins at angular velocity \omega about its center (which is the origin). What is the current I, in terms of given quantities? What is the volume current density J in...

Homework Statement An anti-Helmholtz pair consists of two circular coaxial current loops each with radius R and spaced a distance R apart from each other. The loops carry current I in opposite directions. 1) Calculate the magnetic field and the magnetic field gradient along the axis at the...

Homework Statement The electric field in a region of space has the components Ey = Ez = 0 and Ex = (4.00 N/C·m) x. Point A is on the y axis at y = 3.60 m, and Point B is on thex axis at x = 3.00 m. What is the potential difference VB − VA? Homework Equations Vb- Vi = -∫ba E * dS The Attempt...

Homework Statement https://www.dropbox.com/s/w8xmgdwwqalymm4/000407.png?dl=0 Homework Equations I am not sure. The Attempt at a Solution I really don't understand how to go about this. I really need someone to help walk me through this where I can ask questions along the way. It is not so...

Hey guys I'm a sophomore in college currently taking physics 2(intro E&M), Multivariable calculus, and Differential Equations. I was hoping some of you guys could recommend some good books for intro mechanics and E&M. I'm currently using University Physics by Young in my E&M class, and I used...

I will be transferring from a community college to a university where I will be taking Physics II. We will cover electricity, magnetism, waves, optics, and perhaps even some modern physics. The catalog at my new university says that a co-requisite is Calculus II where they cover integration...

Hello all, I've looked around and it seems the general consensus is Purcell for E&M. I just wanted to make sure that these textbooks would align with my syllabus for E&M. Now there is a little thing I need to add. I'm doing Mechanics and E&M at the same time. I've previously taken AP physics A...

I'm looking for suggestions of resources to learn introductory E&M and "modern physics" (I'm thinking relativity, QM, particle) conceptually. This learning is out of self interest. While my focus is for conceptual understanding, this doesn't mean any suggested resources should be devoid of...

Hi, I've been struggling on this homework problem for quite a few hours now and would really appreciate a pointing in the right direction. It's a fairly entertaining problem that I'm getting stuck on in several places. 1. Homework Statement The problem goes: "An erratic engineer, who lives in...

1. The question: This question is from purcell's E&M book (3.71). (a) The plates of a capacitor have are A and separation s (assumed to be small). The plates are isolated, so the charges on them remain constant, the charge densities are +-σ. A neutral conducting slab with the same area A but...

Can anyone recommend a good book that deals with the mathematics of E&M? I've read through my calculus books and feel like I understand the material there and can solve the problems. However, when it comes to it's applications in electricity and magnetism I find that I have enormous difficulty...

So, I am deeply unsatisfied with the way I've been taught E&M and thermodynamics in school. Despite having done AP Physics C: E & M and having got a 5 in it, I feel my understanding is lacking. Could you guys ( and girls) please recommend something rigorous for me to use to teach myself.Books...

Does anyone know how much undergraduate E&M you need to know in order to do well in a graduate engineering Optics course? Is it an absolute pre-requisite?

Hi! I am writing a calculus-based HTTP://textbook.scotthill.us. It is an HTML-based book with animations, interactive demos, quizzes, and so forth. The first draft is almost complete (I still have to write chapters on integration, induction, and wave optics), but I wanted to share it with a...

Homework Statement I two concentric metalical spheres r1 =/= r2. What to do to have: a) potential energy = 0 and electric charge =/= 0 b) potential energy =/= 0 and electric charge =0. In eighter one of the spheres. Relevant equations Gauss law. The Attempt at a Solution a) If I charge the...

Hello, Apologies for the squished title. Basically, I'm wondering how important E&M and RF/microwaves will be once I obtain my BSEE and search for my first job. I did some research on the forum already and people said that these skills are 'in demand,' and I just wanted more clarification on...

Homework Statement 1.12 - Prove Thomson's theorem : If a number of conducting surfaces are fixed in position and a given total charge is placed on each surface, then the electrostatic energy in the region bounded by the surfaces is a minimum when the charges are placed so that every surface...

Homework Statement http://apcentral.collegeboard.com/apc/public/repository/_ap06_frq_physicsc_em_51784.pdf Please please check out Q2 part (d) on this test Homework EquationsThe Attempt at a Solution I understand that before S2 is closed, current through the circuit is zero. As soon as S2 is...

I'm an EE major doing a minor in physics. I have to take a standard intermediate electromagnetism course from the engineering department (which is just a more applied version of the physics department course). To get my minor, I was thinking about getting permission to use this course as a...

Homework Statement How large an inductance should be connected in series with a 120 volt (rms), 60 watt light bulb if it is to operate normally when the combination is connected across a 240 volt, 60 Hz line? (First determine the inductive reactance required. You may neglect the resistance of...

I am reviewing in Griffith's E&M, and I find that potential is defined as zero at infinity (that bits fine). However, should not an object that distance from a charge be less than zero (negative) if it is closer than infinity? It seems it should as it has lost P.E. However, he doesn't seem to...

Homework Statement The problem states, "Find the electric field a distance z above the center of a square loop (sides of length a) carrying a uniform line charge λ. " The hint says to use the result of example 2.1. Example 2.1 is a similar problem, but instead of a square loop you are asked...

Okay, so I'm a first-semester junior in college, and currently have a 4.0. I'll cut to the chase. I'm in E&M (which I love, I think it's fascinating), and last night I had a test that didn't go so well. It's not that I'm not capable, but for some reason a 4-hour test that begins at 8 PM just...

Is it weird that I find physics II easier than physics I? I am currently in Physics II at university and flying through it with an A. However, I took Physics I at Community College and BARELY got a B. On my tests so far this semester I got a 87 on the first one and a 97 on the second one. In...

I liked my previous courses in statistical mechanics and fluid dynamics, however I don't really like E&M, especially at the Jackson level. I am thinking about doing research in plasma physics. Would I hate plasma physics if I didn't like electrodynamics? Or is that not an issue and does plasma...

In the Princeton Review Cracking the AP Physics C Exam 2011 Edition book on example 11.9's solution, one of the batteries' terminals are swapped (the battery with 10V). I am not sure why the author's do this considering the current is drawn the same. Later on in the solution, they recognize...

this is a homework problem i realized after posting it. so could a moderator please move this question to the homework section? thanks one of Griffiths' example: A primitive model for an atom consists of a point nucleus surrounded by a uniform charged spherical cloud of radius "a". Find the...

Greetings, I have two semi-related questions. 1. When making the Lagrangian formalism of electrodynamics, why is it that we use the Lagrangian density \mathcal{L}, rather than the plain old regular Lagrangian L? Is this something that is necessary, or is it more that it is just very...

So, I graduated last year and decided to spend the year working before applying to grad school. I'm trying to narrow down what fields I want to look at, so I'm collecting information. To that end, my current question is this: "What fields of physics, as common defined by grad-school program...

Hi everyone. I don't know whether this is an advanced or introductory topic but I I've always wondered how to prove symmetry arguments in electrostatics, magnetostatics etc mathematically. Suppose you have an infinite line charge and you need to calculate the electric field at some distance...

Briefly, a solenoid valve utilizes a solenoid to move a soft iron core in such a way as to open/close an orifice to allow/inhibit flow of a fluid. I am a bit rusty on my E&M and I have a couple questions about this operation. 1) When a magnetic field is created using the solenoid, the soft...

Homework Statement There is a sphere of uniform charge, with a hollow sphere inside it, centered on the x-axis. Show that the electric field in the cavity is constant, and find its value. Homework Equations The Attempt at a Solution The problem suggested to use superposition. So...

A high Q antenna basically means the antenna stores a large amount of energy in the near fields compared with the electromagnetic energy radiated per cycle? When the alternating current momentarily stops in our half-wave antenna charge density is maximum at the ends of the antenna, and the...

Homework Statement A proton (charge +1e and mass 1.67e-27kg) and an alpha particle (charge +2e and mass 6.64e-27kg) are placed 3 fm (1 fm=10e-15m) apart. a)what is the force on each particle B)what is the potential energy of the system? c)what is the acceleration of each particle at the...

E&M Problem -- 2 Charged Masses Hanging on Strings Homework Statement Two charges of identical mass m, one with charge q, the other with charge 2q, hang from strings of length l from a common point. Assume q is sufficiently weak so that any angle you're looking for is very small, and find...

Hello everyone. I'm really struggling to simulate a cavity problem. My goal is to be able to know what's going to happen if i introduce spatially dependent phase inbetween mirrors of a cavity that supports certain transverse modes. Well, i believe solving for eigenmodes of a cavity is...

I remember when I took E&M my teacher said that special relativity was built into Maxwells equations. Let's look at a line charge moving at non-relativistic speeds first. We use amperes Law to find the B field. frame 1: B=\frac{\mu_0 v \lambda }{2 \pi r } frame 2: relativistic speed...

As the title says would it be an overload to take all those classes together? I am wondering because these classes are only offered in the fall semester and I plan on taking the physics subject GRE next fall. What should I expect? Any input would be helpful thank you!

I have been learning a lot of the Math in parallel with Physics so I'm not sure how many of my issues are Physics issues or Math issues. I feel like some of my Physics issues could be Mechanics issues. Is it better to retake Mechanics or move on to EM 2. If I do take EM 2 I'm wondering...

I am a sophomore applied mathematics major and would like to teach myself some physics. I can I would like suggestions on a good book on intermediate mechanics. I have looked up the pre-reqs at my college and I have already have taken those classes. I would like a book that has worked out...

A conducting disk is rotating under a uniform magnetic field. Using Lorentz force F = qv x B, we can conclude that emf produced. Using Faraday's law, ∫E dl = 0 for any closed loops since there is no magnetic flux change. So E = 0. Contradiction ?

Homework Statement Could somebody help me on the problems given in the attachments? I know E&M well but these problems stumped me(In the RC Circuit I need help only on part (d) of the question). Tomorrow is my AP C E&M exam. I am too nervous about it. Based on how these problems stumped me, do...

Homework Statement Part f. Calculated current = 0.5 A. Voltage = 30 V. Resistance = 40 Ω Homework Equations P=IV P=I^2*R P=V^2/R The Attempt at a Solution I've been curious about this for a while. Sometimes when I am asked to find the power dissipated through a resistor, and...

Homework Statement Answer is B. Answer is E. Answer is E. Homework Equations E=F/q E=V/d Right hand rule for inductors The Attempt at a Solution Quite confused for these problems. For number 18, I'm quite baffled as to where the 0.04 meters even comes from. What I had...

Hello! When studying the law I noticed that the change in magnetic field (i.e the magnet's motion) is = to the EMF induced. That proofs to me how the principle of the conservation of energy is applied to the world of electromagnetism as well! The energy applied to move the magnet is...

The equation for the change in momentum for total absorption of electromagnetic radiation is ΔU/c and that for total reflection is (2ΔU)/c. How could the momentum of electromagnetic radiation change if it is massless and travels at a constant speed c? Is the ΔU just a representation of a change...

I'm currently taking the EE version of E&M 1 this semester and I'm fairly disappointed in how my professor is handling the material. Every problem is highly symmetric I honestly haven't actually evaluated an integral all semester. The integrals are just remembering the surface area or volume of...

Don't care for Griffiths, and I think it would make a lousy reference given how many important theorems, results, etc. are hidden in the problems rather than included normally. I'd like a book that ideally has derivations of all the relevant formula and CONCEPTUAL descriptions of phenomena...