Magnetic Definition and 1000 Threads

Homework Statement Homework EquationsThe Attempt at a Solution In this problem as the rod moves towards right, magnetic force of magnitude ilB starts acting towards left on the rod.This decreases the speed of the rod .The EMF induced in the rod is Blv where v is the instantaneous speed of...

I'm reading about the theory behind MRI, specifically from Farr's Physics for Medical Imaging, 2nd Edition, by Allisy-Roberts and Williams. According to this book, the spins of the free protons in a sample line up, either parallel or antiparallel, with the externally applied magnetic field. In...

Homework Statement https://imgur.com/gallery/vCOZq Its question 26, and the figure can be seen at figure 30.26 Derive and expression for the magnetic field produced at point P due to the current carrying wire shown in figure 30.26. The curved parts of the wire are pieces of concentric...

Homework Statement A wire 1.0 mm in diameter carries 5.0 A distributed uniformly over its cross section. a) Find the field strength 0.10 mm from its axis. b) Find the field strength at the wire’s surface Homework EquationsThe Attempt at a Solution I've used the Biot-Savart Law for a wire for...

Homework Statement (a) What voltage will accelerate electrons to a speed of ##6.00 \times 10^{-7} m/s## ? (b) Find the radius of curvature of the path of a proton accelerated through this potential in a 0.500-T field and compare this with the radius of curvature of an electron accelerated...

Hello all; I am new in this forum, currently in High School. For some time now, I have been looking online for a relationship between temperature and magnetic flux density of a ferromagnet; below the Curie point. However, I can't seem to find any relationship or formula. Do any of you know...

PICTURE INCLUDED 1. Homework Statement A piece of wire is bent into an isosceles right triangle whose shorter sides have length a The wire carries current I. Calculate the magnetic field for point P. Point P is located on the Y-axis ( 0, √2a). Two corners of the triangle are are located at...

If I keep iron fillings on a cardboard with a wire carrying current in some direction, I know that the fillings will orient in concentric circles.But what happens if I keep the fillings on the underside of the cardboard? Is it possible to make them hang in the air against gravity with a...

As a SP phenomena I thought this may be the best sub to post this. We understand how current creates a magnetic field, and almost all forms of current are really electron flow. My question is - are there any known (real world) examples of positive particle flow, creating a magnetic field...

Homework Statement The Lorentz Force can be used to sort ions (atomic or molecular) based on their charge to mass ratio. This configuration has been used to separate isotopes and as a mass spectrometer. A beam of Strontium ions Sr+ is accelerated through a potential of 500 V and injected into...

Is it a magnetic or an electric field that causes induction in the antenna wiki says that: The electric field (E, green arrows) of the incoming wave pushes the electrons in the rods back and forth, charging the ends alternately positive (+) and negative (−). enter image description here...

Homework Statement In a homogeneous, non-magnetic, highly insulating and viscous medium, a moving particle experiences a viscous drag given by the law f→=−bv→. Here b is a positive constant. A particle having charge q is projected with an unknown velocity from a point in the medium. It almost...

Hi, initially I am aware that magnetic flux is conserved due to divergence of magnetic field is zero and for long solenoid, magnetic field inside is uniform. So magnetic field intensity (B) at point P,Q,S, T,R,U(in the attachment) must be same. But my question is : can we obtain the same...

Homework Statement Find the magnetic moment of a crystal when placed (i) in a weak field at high temperature (ii) in a strong field at low temperature Homework Equations This is the last part of a question which I feel I have solved correctly up until this point. The mean magnetic moment I...

I was reading the statistical physics textbook and was really confused with the notation: I don't understand the last part of the section. Why is that \sum_{\sigma = \pm1} \sigma P(\sigma) equals to \left< \sigma \right>? And what does \left< \sigma \right> actually mean? Is it the average...

Let's consider that I have an emitter that can emit both negative and positive electric charges. Here let's consider only scenarios with two particles (one negative and one positive) that start initially at the tip of some electrode, where one or both the charges will separate from at the same...

Homework Statement suppose we have a charging capacitor orientated along the z-axis, such that we have a changing electric field. How do I determine the direction of the associated magnetic field. Homework EquationsThe Attempt at a Solution I calculated the magnitude of the B field, and my...

Homework Statement Jupiter has the strongest magnetic field in our solar system, about 14 G at its poles. Approximating the field as that of a dipole, find Jupiter's magnetic dipole moment radius= 69.9*x10^6 Homework Equations u=2UB or T=U*B The Attempt at a Solution T=...

If a current flows in a straight wire, a certain amount of magnetic flux will be generated around it. Now suppose I put an iron tube around the wire (but don't change the current). I know the inductance will increase, but is that because more total flux is now being generated, or is the total...

Homework Statement Homework Equations This is the way to solve when magnetic field B is arbitrary direction one. The Attempt at a Solution I got a eigenvalue of this Hamiltonian and eigenstates. but i have no idea how to set a coordinate to value the gradient

Hi all, This question has been bothering me for some time, so here it is. I know that moving a charged particle, like an electron, generates a magnetic field. I know that moving electric charges in a circle (a loop of wire) generates a magnetic field. The question is, will a charge moving in a...

To my understanding, photons have no charge, so how does the magnetic field control them. Also side question - in the diagrams I see the photons seem to kind of curve around the magnetic field, does that mean they are accelerating?

Homework Statement [/B] I have been given an equation for the magnetic potential of a buried magnetic object which is as follows Pm=α/x2 Where α is some constant and x is the distance from the magnetic body. I need to derive an expression for the magnetic field strength at some distance x...

Let's say that there's nothing else in this universe except for 2 charged particles: q1 and q2. q1 is moving relative to q2, moving at velocity v. I've read that a magnetic field is made by a moving charge. In this case, the moving charge q1 is moving relative to q2. What would the magnetic...

Homework Statement The circuit in Fig. 32-31 consists of switch S, a 12.0 V ideal battery, a 20.0 M resistor, and an air-filled capacitor. The capacitor has parallel circular plates of radius 5.00 cm, separated by 3.00mm. At time t=0, switch S is closed to begin charging the capacitor. The...

Hello! I've made a lot of research about measurement of high magnetic fields - such us 1T - 2T and I can't find sensors for this range. I'm looking for a hall sensor with which I will be able to measure 1T magnetic field with good accuracy - about 0.1 mT. Do you know about anything like that...

1. Why is Earth's South Pole called its North Pole? Why hasn't it been changed to make it more scientifically accurate? 2. Why are the North Poles of other planets defined relative to Earth's 'North' Pole? Why isn't it based upon the actual direction of the planet's magnetic field?

Hello everyone, This is my first post here Firstly, I'd like to start by saying that it's my best intention to follow the rules on this forum. Therefore, if I've posted this in the wrong section please forgive me, I will try and learn the ropes quickly. One of my students has given me some...

So I know if you move a charge in a magnetic field it induces voltage and hence a flow of charge is created which is current. ( Please correct me if I'm wrong). But that's pretty basic right. However, I'm having trouble understanding the use of split rings in the functioning of a motor. I would...

Homework Statement In Fig. 32-9 there is a + x-directed uniform magnetic field of 0.2 T filling the space. Find the magnetic flux through each face of the box shown. Homework Equations ΦM = B ⊥ A = BA cos θ The Attempt at a Solution My attempt is attached to this post. How do I determine which...

HI, I have application where i need to lift metal plate, 3kg weight, ( 3mmX 15mm), 250degree.C hot, for the period of 1min and put it back. For lifting purpose i am using actuators. As i have no opportunity to make hole in plate i have to use magnet for lifting purpose. I got Electromagnet...

Homework Statement Two long fixed parallel wires, A and B, are 10 cm apart in air and carry 40 A and 20 A, respectively, in opposite directions. Determine the resultant field (a) on a line midway between the wires and parallel to them and (b) on a line 8.0 cm from wire A and 18 cm from wire B...

Homework Statement Hamiltonian of charged particle in magnetic field in 2D is ##H(x,y,p_x,p_y)=\frac{(p_x-ky)^2+(p_y+kx)^2}{2m}## where ##k## and ##m## are constant parameters. For separation of this system use ##S=U(x)+W(y)+kxy+S_t(t)##. Solve Hamilton - Jacobi equation to get ##x(t), y(t)## ...

I'm trying to understand the repulsive forces of solenoids. This is all paper as in I don't actually have them to test in real life. Take two solenoids that are equal to each other. Specifications: current is 10 amps Number of turns is 300 Iron rod is 12 inches/ 304.8mm, with a Radius of 2...

Hi all, Consider one has a magnetic dipole, the field given by: \begin{equation} \vec{B} = \frac{\mu_0}{4\pi}\left(\frac{3(\vec{m}\cdot\vec{r})\vec{r}}{r^5}-\frac{\vec{m}}{r^3}\right) \end{equation} where we can take $$\vec{m} = m\hat{y}$$. Let us say we have the a magnet vector which is...

This Science news article describes efforts to treat cocaine addiction by activating or inhibiting specific brain circuits with Transcranial Magnetic Stimulation (TMS). TMS works by producing magnetic fields close to the scalp which in turn induce currents in different brain areas. This can...

Homework Statement Uploaded question(the formula in c part) And can you tell me in which all cases that formula is used. Homework Equations Just want to know where the formula in c part has come from. The Attempt at a Solution Sum of magnetic fields due to circular plates calculated and added...

I am trying to understanding magnetism and I've been running into this thought problem A particle a in a magnetic field B responds with Force F=|q|v x B. frame S: The field is B1, caused by a moving charge/s - current at speed v. the particle is at rest, F=0. frame S' moves with speed v/2...

Why are they circular? You know, like this: Why not straight toward the wire?

Homework Statement Homework EquationsThe Attempt at a Solution Because of the external magnetic field ##\vec B_0 ## , a uniform magnetization will be in the direction of external magnetic field. Because off this uniform magnetization, there will be a uniform magnetic fied in the direction of...

Hi everyone, I have recently done an experiment testing the effect of temperature on magnetism through measurement of magnetic flux at a constant distance away from the measuring device. I used a range of 0-90 C for neodymium and bar magnets, and found a reasonably linear trend, with a similar...

If electrons have a magnetic moment (or behave like they have) why don't all orient North Up in a magnetic field (pointing down)? Plus, if thought as magnetic dipoles, like poles repel, therefore all should point the same direction. In a Stern-Gerlach apparattus shouldn't the magnetic moment...

Situation is this, consider a conductor moves perpendicular to the direction of magnetic field. But magnetic field is not uniform through out the conductor movement( but magnet is stationary and flux lines are in same direction and magic field doesn't change with time but changes with space...

1. Homework Statement Hi. This is my first question on PF so please forgive me if something's not right So I'm stuck at this question in EMT In frame1, E and B are parallel and related by E=cB. We are required to find the cosine of the angle between electric field E' and magnetic field B' in...

Dear all, I know the sources of magnetic field are moving charges or varying electric field. I also know that subatomic particles(even neutron) have their own magnetic moment due to its quark and spin and their magnetic moment is explained by invoking quantum mechanics(though I don't know how...

When a magnetic field is applied across the left part of the tube , it's level rises as shown . I would be grateful if someone could help me understand why this happens . Thanks .

Homework Statement To find the direction of magnetic field due to a toroid. Homework EquationsThe Attempt at a Solution Taking the cross - sectional shape of toroid circular, the toroid could be turned into a solenoid. A solenoid's magnetic field is along its axis. When the solenoid gets...

I have seen a formula for magnetic pressure ##P_M=\frac{B^2}{2\mu_0}## Where does it come from? How my I derive it?

Homework Statement Decide the direction of Magnetic field of a very long solenoid consisting of n turns per unit length on a cylinder with current I flowing through. Homework EquationsThe Attempt at a Solution Deciding direction of the magnetic field: Considering cylindrical coordinates with...

Is it possible to have a magnetic field of a any geometry we want, or there are only few types of geometries that can be achieved with permanent magnets and electromagnets? If the former, how do we produce a magnetic field of specific geometry? For example, can the magnetic field be cylindrical...