Electricity and magnetism Definition and 210 Threads

Homework Statement Two concentric circular coils of wire lie in a plane. The larger coil has 61 turns and a radius of a = 7.40 cm. The smaller coil has 58 turns and a radius of b = 0.95 cm. The current in the larger coil has a time dependence as shown in the figure. Picture and graph...

Homework Statement There is a solid cylinder of radius a and then empty space then a shell cylinder of radius b. Show that half of the stored potential energy lies within a cylinder of radius $$\sqrt{ab}$$ Homework Equations In the attempt The Attempt at a Solution I'm not sure what they...

Dear all, I'n an EE that finished his degree more than 10 years ago. I wanted to refresh my Electricity and Magnetism knowledge. I bough Purcells book some weeks ago (https://www.amazon.com/dp/1107014026/?tag=pfamazon01-20) and I'm kind of struggling through the maths (Vector calculus). I've...

Homework Statement A dielectric sphere of radius R with uniform dielectric constant ε has an azimuthally symmetric density charge σ = σ0 cos θ placed on the surface. Outside the sphere is vacuum. (a) Obtain the electrostatic potential inside the sphere, φin. (b) Obtain the electrostatic...

Homework Statement Referencing the attached picture: a) Show that the RMS current in the 1 kΩ resistor is 6.5mA. b) If the AC voltage source was replaced by a battery, what would the current in the resistor be? Homework Equations V = IR Z = √(R^2 + X^2) The Attempt at a Solution To begin, I...

Homework Statement https://gyazo.com/d502fb408d6224ffa70700cf047bad20 (link to problem: #4). [moderator edit: Image inserted for clarity] A total charge Q is distributed uniformly over rod length L. The rod is aligned on the x-axis, with one end at the origin and the other at point x=L. a)...

So I am constructing an analogy between the self replicating fracturing effect on thin films and the path of a charged particle. (Qualitatively, several cracks have similar shapes to charged particle motion) I won't go into the details of the fracture mechanics, so I will only use E+M...

Hello, I will be taking a second course on electromagnetism and I want a book that bridges the gap between Griffith's book and Jackson's book. I have come across Panofsky's book and Nayfeh's book but I don't know which one is better. Any opinion for these would be much appreciated Thanks!

The graph below shows the efficiency of an AIR CORE transformer at different voltages (from MAINS). At low voltages, it has high efficiency and gets lowers because of high magnetising current causing heat loss. But why is it higher at some points again? I do not understand this pattern. Please...

Homework Statement We want to calculate the field of a uniformly polarized sphere of radius=R Homework Equations V(\vec{r}) = \frac{1}{4 \pi\epsilon_{0}} \oint_{S} \frac{\sigma_{b}}{r} da' + \int_{V} \frac{\rho_{b}}{r} d\tau' The Attempt at a Solution i)I know that \sigma_{b} = P...

Homework Statement Excess electrons are placed on a small lead sphere with mass 8.00g so that it's net charge is -3.20x10^-9C (a) Find the number of excess electrons on the sphere. (b) how many excess electrons are there per lead atom? The atomic number of lead is 82, and its atomic mass is...

Hi people! I am a high school rising senior who is looking to self study electricity and magnetism over the summer. Particularly, my aim is to take the ap physics c electricity and magnetism exam as a result of this self study but also to realize if I want to work with hardware/electrical...

Okay, so I'm working with the diagrams above. ##i## denotes incident, ##r## reflected, and ##t## transmitted. -We're working in two HIL dielectrics. Incoming and outgoing waves are of form ##Aexp[i(\vec{k}\cdot\vec{r}- \omega t) ##. As I understand it, Maxwell's equations give four boundary...

Homework Statement http://imgur.com/AotzH28 Two long, straight conducting wires with linear mass density λ are suspended from cords so that they are each horizontal, parallel to each other, and a distance d apart. The back ends of the wires are connected to each other by a slack,low-resistance...

Homework Statement Current density is the amount of current per cross sectional of flow. I'm having trouble wrapping my head around this definition. Surface charge or volume charge I understand better since they are almost analogous to the density we all understand (amount of matter/charge...

Homework Statement Homework Equations The voltage between any two points due to the field from a point charge q is: Kirchoff's voltage laws, which states that the total voltage around a closed loop must be zero, i.e.: The Attempt at a Solution To find V(e<-d) I used Kirchoff's...

Homework Statement A square wire loop 12.0 cm on each side carries a clockwise current of 15.0 A Find the magnitude of the magnetic field at its center due to the four 1.30 −mm wire segments at the midpoint of each side. Homework Equations B = (μ0*I)/(4π)*(2a)/(x√(x^2+a^2)) The Attempt at a...

Homework Statement A square wire loop 12.0 cm on each side carries a clockwise current of 15.0 A Find the magnitude of the magnetic field at its center due to the four 1.30 −mm wire segments at the midpoint of each side. Homework Equations B = (μ0*I)/(4π)*(2a)/(x√(x^2+a^2)) The Attempt at a...

Homework Statement Fig. 25-39 shows a 12.0 V battery and four uncharged capacitors of capacitances C1 = 1.00 µF, C2 = 2.00 µF, C3 = 3.00 µF, and C4 = 4.00 µF. If only switch S1 is closed, what is the charge on (a) capacitor 1, (b) capacitor 2, (c) capacitor 3, and (d) capacitor 4? (figure at...

Homework Statement Charges 2q and -q are located on the x-axis at x=0 and x=a respectively. (a) Find the point on the x-axis where the electric field is zero, and make a rough sketch of some field lines. (b) You should find that some of the field lines that start on the 2q charge end up on...

1. The problem: A Geiger-Mueller tube is part of a Geiger counter, a device used to count the number of ionizing particles passing through it. It consists of a conducting outer cylinder held at zero electric potential with a thin central wire held at an electric potential of roughly 1000 volts...

Homework Statement Two small objects of equal mass 3.0g are placed a certain distance apart. How many electrons must be transferred from one to the other so that the electric force between them is equal to the gravitational force between them? Homework Equations Coulomb's Law: F = K...

For our physics class we have to design an experiment investigating the factors affecting an electromagnet's field strength. I have decided to investigate the number of coils in the wire. My only problem is, I'm not sure how to measure the field strength. Our teacher gave us two things which we...

Homework Statement A charge (q) is placed in-between two other equal charges named Q. Q-----q-----Q a) If both Q's are positive, is charge q in equilibrium? If yes, is it a stable or unstable equilibrium? b) What about if one Q is negative while the other is...

In chapter 5 of Purcell's Electricity and Magnetism, he shows using principles of special relatives that the magnetic force of a current carrying wire on a moving charge is equivalent to the charge experiencing an electric force in its own frame of reference. His argument is that when the...

The 4 questions have been uploaded as 2 jpeg files. I need step by step proper solutions as a pdf or word file if possible. Please help. Send the solutions to my email id : pyplx7x@gmail.com

Hello, Am starting to read Electromagnetic Theory. Can you suggest some good textbooks on the topic that will help clear the concepts. Thanks in advance

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...

Homework Statement http://postimg.org/image/vzhqi8er5/ Homework EquationsThe Attempt at a Solution I understand all the calculations here - http://www.physicspages.com/2012/10/18/coaxial-cable-with-dielectric/ I have one issue that is bugging me though - if λ charge density is distributed over...

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...

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...

Let's say I place two different size conducting loops inside of a uniform magnetic field. For the sake of the diagram I have the loops share a point, but just treat them as though they are not touching. Then I decrease the value of the magnetic field very quickly. \frac{dB}{dt} =...

Hello, my name is Israel and I have a B.A. in physics from California State University Stanislaus. I graduated in 2011 in the worst economy ever and in the worst part of the U.S. to be hit by the great recession. I have substitute taught in every subject in K-12, but I am looking to get into the...

Homework Statement Consider an ## n ##-dimensional solid sphere of radius ##R##, with uniform charge-density and a total charge ##Q##. A charged particle ##q## is kept at a distance of ##r## from the center. For ##r<R##, what is the Net Coulombic Force experienced by the particle? If it is in...

Edit: sorry i realized i posted this in the wrong section. Can some move it to hw? Thank you. Hey i was s[SIZE=16px]tudying intro E&M recently and i started learning about RC circuits. Up until this point everything, concept wise, has made sense for me. Then I learned how RC circuits work, and...

The book I am working through is beginning to dive into induced currents and Lenz's Law. When a conductor is moving perpendicular to a magnetic field, the charge carriers inside will experience a magnetic force; This causes the charges to move. Eventually, the electric field from the charge...

I was wondering if I could ask a question on the magnetic field surrounding a current-carrying wire, and how this field might change with the presence of other, ferrous materials nearby. I have been using this web page http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html#c3 to...

First in Circuit A: I hook up a battery with a voltage of V up to a capacitor C1. Once C1 is fully charged it has 6+ on its positive plate and 6- on the negative plate. Given it's fully charged, the +terminal of the battery and the +plate are in electrostatic equilibrium. Since they are both in...

I am interested in calculating the magnetic field around a wire. Using the formula found here http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html#c3 I can calculate that B = (μ0*I)/(2*pi*r) Where I equal current in Amperes, and r equals distance from the wire in meters. This gives...

I took a college physics course (Mechanics) at a CC, and my physics prof was notoriously known to be one of the best... many of the students transferred to Berkeley and say that he is one of the best they have taken. He said that his two favorite book are: Halliday Resnik: Fundamentals of...

I am studying about transformer and get confused about some concept. I have learn that in an ideal simple transformer the primary has two components of current: Magnetization current i.e. the open-secondary primary current. Current that (ignoring small leakage inductances) finds it way (via...

Hi, I'm looking for some great books clearly explaining how electricity, magnetism and electromagnetism Works. I'm also looking for some books describing how it was discovered and what experiments have been performed in discovering how it Works,. So Far I've looked at Electromagnetism...

At the exact center of a finite wire (i.e. a distance, say $L/2$ from each end), why can I not apply Gauss's Law in integral form to find an EXACT solution for the electric field? At the center of the wire, $E$ is entirely radial, so it seems like I should be able to draw an infinitesimally...

I am supposed to graduate next year but I just realized I have left Electricity and Magnetism off of my schedule. I'm afraid to add it because I feel like I am already taking enough and I am wondering if instead it is common or likely to just take the undergrad elective in graduate school. I...

Why flowing current in wire creat magnetic field...if anybody say this is because of spin quantum number,... So i just want to say spin quantum number is because of wave nature of electron.i just want to know what effect of dual nature of electron on magnetic field.:rolleyes:

I have been thinking about coils of wire carrying alternatingcurrent. From what I understand, a back emf is induced in the coil because there is a changing magnetic field around each individual loop of wire, and therefore there is a changing flux through each loop because the changing field...

i have heard it said that back force occurs in generators and back emf occurs in motors, however I was considering a motor and I thought that it seems to me that as the coil is rotating and it has the changing flux linkage, and thus a back end is induced in it by Lenz's law, this reduces the...

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 want to build an electromagnet which can attract small iron pieces(2-3 mm long) at a distance of 10 cm from the magnet.I am using 24 awg. magnet wire.Please help .answer these questions - 1) How long magnet wire (24 awg) do i need? 2)How much current 3) what shud be least radius of solenoid 4)...

Homework Statement An infinitely long hollow cylinder of radius (a) carries a constant current (i). Use Biot - Savart's law and show that the magnetic field at the centre of the cylinder is zero. Also show, using symmetry arguments and Ampere's law, the magnetic field is zero in any point...