Magnetic field Definition and 1000 Threads

In class while learning about electromagnetism, I was given the following two equations: U=-μ⋅B τ=μ×B where μ=IA First of all, what does μ stand for? How should I interpret the relationship between potential energy (U) and torque? Can someone explain this in terms of μ and B?

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?

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...

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...

<Moderator's note: Moved from a technical forum and therefore no template.> Homework Statement A proton (q = 1.60 x 10-19) is in a uniform, 0.500 T magnetic field. This proton has velocity components vx = 1.50 x 105, vy = 0, and vz = 2.00 x 105 m/s. Find the force on the proton at t=0. 2...

Homework Statement A uniformly magnetized and conducting sphere of radius R and total magnetic moment m = 4\pi MR^3/3 rotates about its magnetization axis with angular speed \omega. In the steady state no current flows in the conductor. The motion is nonrelativistic; the sphere has no excess...

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)## ...

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?

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...

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...

This Wikipedia article https://en.m.wikipedia.org/wiki/Relativistic_electromagnetism seems (to me) imply that there is always a frame of reference in which a magnetic field can be rather viewed as an electric field modified by relativistic considerations. Is that always true? That is...

Homework Statement Homework Equations N/A The Attempt at a Solution Im not sure if I've done this right because it seems too little for 6 marks. I have arrows coming from the north to the south end for the magnet's magnetic field. I have arrows going counter clockwise around the conductor...

If I do the x-axis rotation for a solenoid, how will the magnetic field change? Would it also rotate along x axis?

So are there photons "flowing" from one end of a permanent magnet to the other? If so what determines the frequency?

Homework Statement Find the magnetic field at the point distance R outside a rectangular loop of sides 2R, 4R carrying current I as shown in the attached diagram Homework Equations Biot-Savart Law The Attempt at a Solution Could I just break this up into 4 separate lines and then calculate...

How does look like electric field lines due to change of the uniform magnetic field? Suppose we have a magnetic field between two infunite plates with surface current $i$ which is lineary change with time. Then B-filel is (x - perpendicular to plates, z and y along plates) \begin{equation} B_z =...

Homework Statement What direction does the force that the current carrying coil feel point to when a magnetic field is turned on? A magnetic field is turned on and points from bottom to top and passes through a current carrying coil that has current passing through it CCW. Here is a diagram...

Homework Statement Homework EquationsThe Attempt at a Solution using the left hand rule, second finger points the direction of current, thumb points direction of motion and first finger the direction of magnetic field. But If direction of current and motion is the same, what do I do? Thanks~

Homework Statement Homework EquationsThe Attempt at a Solution I know if the currents are going the same direction they attract. So the top 2 attract each other and the bottom two attraction each other? And then the top repel the bottom... I'm stuck, please help~

Homework Statement Homework EquationsThe Attempt at a Solution Shouldn't they be the same? Does one being above the current and the other being below make any difference? I know when there is a higher density of magnetic field lines, the magnetic field strength is greater, but in this case...

Homework Statement What is the force on an electron with a velocity v = (2i – 3j) Mms-1 in a magnetic field B = (0.8i + 0.6j – 0.4k) T Homework Equations F=qvBsinθ The Attempt at a Solution using cross product I got: (1.92i + 1.28j + 5.77k)10^-13 N which is the listed correct answer. My...

A 2.53*10^(-6) C charged particle with kinetic energy of 0.0929 J is fired into a uniform magnetic field of magnitude 0.147 T. If the particle moves in a circular path of radius 3.38 m, determine its mass in kg. (answer should be within 2*10^-14 kg) The formula r=mv/qb comes to mind where r is...

Homework Statement Two wires with the same intensity but with opposite directions. The magnetic field of the middle line between the two wires is: a) (X) b) (o) c) Parallel between the two wires d) Null e) Non of the above. Homework Equations N/A The Attempt at a Solution Knowing that they...

So if you have a permanent magnet what is moving along the magnetic field lines? Electrons? Photons?

This is one of the big confusions i have. When rotor magnetic field is 90 degrees with respect to stator magnetic field we get maximum torque. In field oriented control the a, b, c axis is converted to d and q axis. So making d axis to 0 and q axis to torque and running through pi loop does...

Homework Statement :A metallic disc of radius R is placed perpendicular to a magnetic field B.Both the magnetic field and the disc rotate with an angular velocity w about the axis of the disc.Find the induced EMF between the center and the circumference[/B]Homework Equations Motional Emf=Bvl...

Homework Statement A group of particles is traveling in a magnetic field of unknown magnitude and direction. You observe that a proton moving at 1.50 km/s in the +x-direction experiences a force of 2.25 x ##10^{-16}##N in the +y-direction, and an electron moving at 4.75 km/s in the -z-direction...

Homework Statement A particle of mass 0.195 g carries a charge of -2.50 x 10-8C. The particle is given an initial horizontal velocity that is due north and has magnitude 4.00 x 104 m/s. What are the magnitude and direction of the minimum magnetic field that will keep the particle moving in the...

I have looked this up on several occassions and never satisfied. It seems that either the answer keeps repeating magnetic or electromagnetic field over and over. Or the answer discuss the properties of electromagnetism. Is the field a wave/particle like a photon ? Is it emitted like a photon...

What would happen if the entire Earth was somehow exposed to a massive magnetic field, such as those found near magnetars, like 10^10 teslas, for about 1 second? Would everyone instantly die? What would be the impact of a moving magnetic field vs a stationary magnetic field be? How much time...

Homework Statement Picture of the problem: I first need to calculate the magnetic field in point P caused by the piece of wire at z = R (so the top wire parallel to the y-axis). Homework Equations [/B] Biot-Savart law for magnetic fields: ##\vec {dB} = \frac {μ0*I} {4*π} * \frac {\vec {dl}...

I am a Graduate student in Electrical Engineering. I have to work on Electromagnetic, Dielectric, Magnetic field and Polarization for my project. But my problem is I do not have a good background in this course. Now, I really need it in graduate level. My question is, can you guys introduce me a...

Hi, for a particular project, I would like to create a 1~2 Tesla magnetic field in a stainless steel pipe along the z axis. I was wondering if my concept would work, or if anyone had better ideas. Here's my concept. Fig1. So I got a few pipes about 1 inch in diameter. I would like to have a...

I am trying to understand the basics of bldc motor. My question is if i am driving the 3 phase motor with sinusoidal waveform. The magnetic field is produced for each phase or it will add together to generate net magnetic field? How to get the net magnetic field.

We know a magnet has field with direction from North to South. Why when a piece of iron come close to the magnet can either be attracted and from both sites and not for example from one pole?

Hello , I am having a slight confusion while reading the chapter on Earth's magnetism . If we place a magnetic compass on the floor I.e on Earth's surface , the North (red) of the compass needle points towards magnetic north of Earth . But would it be correct to say that "the compass needle...

I have been unable to determine whether a Halbach Array of permanent magnets would experience a net force in a uniform magnetic field.

Even if the outer core is convecting and conductive it is still charge neutral, so how can a Magnetic field be generated? Maxwells Equation say there needs to be net charge moving for a Magnetic field to be generated.

I am computing magnetic field around a thick conductor to do railgun force modeling. I am currently re-examining my magnetic field computation, and I have found some confusing results stemming from a fairly simple use of the Biot-Savart Law. The main issue is that the more nuanced application of...