Magnetic field Definition and 1000 Threads

I am not sure that I fully understand even the basic aspects of the Quantum measurement and entanglement but I just came across this thought experiment and I wish to resolve it. In a setting of two entangled spin-1/2 particles, suppose that Alice applies a uniform magnetic field ##B_0## along...

I have some trouble understanding the concept of spin precession in an external field from a quantum mechanics viewpoint. Hopefully someone will be willing to enlighten me. Consider a single spin ½ particle. In the absence of an external field, the projection of the spin angular momentum on...

So a little bit of background: I work in an undergraduate lab at UMass Amherst and am currently building/optimizing a faraday magnetometer for use in the Muon g-2 experiment at Fermilab. The magnetometer works as follows. A laser is shone through a crystal with a particular Verdet Constant at...

What I've not been able to find after literally spending several hours researching is if you can find the formula to find the magnetic field strength from a temporary magnet. Or, to be put in better terms, what would be the force between two objects if one is a magnet and the other is something...

The configuration is hall sensor --- steel rod(3mm radius) --- magnet. Im trying to make a non mechanical endswitch for a sliding lid and want to determine on what magnets to get and how far apart the hall sensor and the magnet should be for it to work in the proper range. The hall chip...

Hello. I'm using CT (Current Transformer) to measure the current flowing on the power line. The frequency of the current is 13.56 MHz. CT appeared to be metal-shielded (This metal case of CT may be grounded when CT is used). CT has a toroidal shape and the power line under the measurement...

https://scontent-ord1-1.xx.fbcdn.net/v/t34.0-12/17092376_1311006885612822_239104452_n.png?oh=72f2336f20f39bd399888901812eae3e&oe=58BAB2BF Hello PF friends. I know what the answer is, but I do not understand why the answer is. By the right hand rule I put my thumb west, but pointer up, and...

Homework Statement A beam of neutral hydrogen atoms in their ground state is moving into the plane of the page and passes through a region of a strong inhomogeneous magnetic field that is directed upward in the plane of the page. After the beam passes through this field, in how many beams was...

So when a conductor in complete circuit is placed next to a moving magnetic field, current in the conductor is induced and the induced current again produces its own magnetic field. So does this new magnetic field act on the conductor? It's the same as the question in the title. Is my concept...

Homework Statement I think this is a 'magnetic mirror' question - the field lines converge on the z axis. For a particle moving into an area of increasing field strength, where the field lines converge. Assume the ##B## field is rotationally symmetric about the ##z## axis, with ##B = B_z...

Homework Statement Consider a charged particle entering a region of uniform magnetic field B - for example the Earth's field. Determine it's subsequent motion when the y-axis is parallel with the magnetic field Homework Equations F=qv x B = ma vector components of velocity, acceleration, and...

Homework Statement See image below. Homework Equations motional emf = induced voltage = B L v The Attempt at a Solution I thought the answer would be A since there's a direct relationship between EMF and magnetic field strength. The answer is D.

Basically my question is: if an anion is placed by the negative poll of a magnet will it push on the particle?

Hello again everyone sorry it’s been a while since last post or question, been working hard and had my nose to the grind stone, face stuck in many books along with heaps upon heaps of magnetic theory and EE lectures muhahahahaha. Ok to the question, I have been having some trouble finding a...

Hello, Let's assume we put a small iron particle in a magnetic field. What is the equation of the route that the particle performs? Is it the minimal route length that is possible? (the magnet is a stick-form)

Homework Statement A magnetic field of 0.0200 T [up] is created in a region Find the initial magnetic force on an electron initially moving at 5.00 X 10^6 m/s [N] in the field. Homework Equations Work clarification and I would like to ask a question in relation to the direction of FM. The...

I need help find a electromagnet suitable for this http://imgur.com/a/vkm4T Each electromagnet (the 3 in the center) needs a repelling force of about 20 to 40lbf. I stupidly bought these from amazon http://a.co/aSftIat. Its a holding electromagnet so the N and S poles are essentially on the same...

Hi, everyone. I am facing issues in trying to solve a problem on a wheel in magnetic fields. Since I was not able to access physicsforums, I wrote up everything about my issues and the question in a pdf file that I am attaching accordingly to this post. It is even typed up in the format of...

Hello A friend of mine asked me if he could improve the (amateur) characterization of minerals by studying the absorption spectra during the application of a magnetic field. I thought that maybe the electron cyclotron resonance could work, but then I noticed that very low temperatures are...

I'm having some trouble with vector potential formulas. Ihave always used this one : A=(μ/4pi )*∫(J/r) dV, where r is a distance. I don't understand where this formulas comes from: 1) A=(1/cr)*∫JdV where c is the speed of light; 2) H=(1/cr) Ȧ where H is the magnetic field's vector. Can...

Hi everyone, I was talking to a friend of mine today who's studying electrical engineering and he essentially asked me why a charged particle feels a force when moving through a magnetic field. I thought about it for a moment, and realized I didn't have a good answer for him. Would anyone be...

A current carrying conductor produces a magnetic field but what if there is an object which has the same speed as current. Will there be magnetic field by the current carrying conductor for that object?

The example: An electron is trapped in a magnetic field. The electron travels along a circle in a clockwise path. It's my understanding that there is a magnetic field around the electron also circulating in a clockwise direction perpendicular to it's path. Now if this electron was in a...

I thought the definition was: a vectorial field that interacts with a moving charge But wikipedia says it's a field generated by electric currents and magnetic materials... https://en.m.wikipedia.org/wiki/Magnetic_field Why is in the definition the way it is Generated? When we had defined the...

I have a doubt on this calculation of magnetic field in presence of displacement current. Consider a capacitor of radius ##R## and with plates at distance ##d## being charged: there is a displacement current in it. Suppose that I want to calculate the magnetic field ##B## at a distance ##r <...

Homework Statement Basically having a problem when trying to theoretically calculate the mass of alpha particle in a charged field. r is the unknown radius of curvature m = mass of an alpha particle (6.646 *10^-27 kg) v = velocity of an alpha particle immediatly after decay (1.381 *10^7 m/s)...

So here is the problem, it asks me to find the total magnetic field on BA, i made a vectorial sum with the magnetic field generated by i1 and by i2 and i got the right result, but why not adding also the magnetic field generated by the wire itself? I mean generated by CD why isn't that correct...

Homework Statement Many sources of electromagnetic waves (stars and light bulbs, for example) radiate in all directions. A simple example of the electric field for a monochromatic electromagnetic wave produced by a spherical source is $$E(r,\theta,\phi,t)=A\frac{\sin \theta}{r} \big(\cos...

Homework Statement A long (infinite) wire (cylindrical conductor of radius R, whose axis coincides with the z axis carries a uniformly distributed current I in the +z direction. A cylindrical hole is drilled out of the conductor, parallel to the z axis, (see figure above for geometry). The...

So my friend was playing around with an electric lighter like the one below and he put the arc through the metal spirals on his notebook. The hole from the spirals was pointed towards his monitor and whenever he touched the arc of the lighter to the metal notebook rings the laptop monitor would...

Homework Statement Two wires are laid side by side and carry equal currents in opposite directions. Explain why the total magnetic flux density due to the current in the wires is negligible 2. The attempt at a solution I know that having a different direction for the current results in...

Homework Statement Homework Equations Flux = DeltaB * Area The Attempt at a Solution : Since the magnetic fields are going in opposite directions through the loop, I assumed that they would have different signs, so I chose 2.0 T to be positive and 1.0 to be negative, so when calculating the...

Homework Statement 1. (35 pts) You have a coop job helping to test a capacitor energy storage system. There is a rather large capacitor with capacitance, C = 2.02F. It is charged to a potential V = 602.V with the polarity of the capacitor as shown. The large, solid line on the right of the R–C...

The hydrogen is placed in the external magnetic field: $$ \textbf{B}=\hat{i}B_1 cos(\omega t) + \hat{j} B_2 sin(\omega t) + \hat{k} B_z ,$$ Using the relation ## H = - \frac{e\hbar}{2mc} \mathbf \sigma \cdot \mathbf B ##, then I got the form $$ H = H_0 + H' , $$ where $$ H'= - \frac{e...

The axis of the cylinder is perpendicular(not parallel) to M, magnetization. It's not hard to find bound surface current density, but it depends on the angle while the answer says the magnetic field is uniform inside the cylinder. Anyone can silve this problem??

Homework Statement A conductor consists of a circular loop of radius R and two long, straight sections as shown in the figure. The wire lies in the plane of the page and carries a current I. (a) What is the direction of the magnetic field at the center of the loop? (b) Find an expression for...

Homework Statement These are two similar questions, one from my previous exam and one from a sample test my teacher provided. I understand how to work the problem, but my question is how is the i or j component decided in each of these?Homework Equations From our formula sheet... The...

1) If the idea that gravity is a curvature of space that causes objects to move towards each other then would it be appropriate to say that magnets do the same thing to space? 2) Does it seem a bit coincidental that both gravity and magnetism operate by the inverse square law or is it possible...

Hi My question is about magnetic field I mean I know where their formulas are derived from amperes law but I didnt really understand why and how there's is a difference in magnetic fields outside and inside a crrent carrying wire the field inside a current carrying wire is B = μoIr^2/2πR^2 the...

An inductor and resistor are arranged in parallel to a constant voltage source. There is a switch connected to a terminal on the inductor that can create a closed loop that includes either the voltage source, or the resistor. The switch is left connecting the source and inductor for a long...

Homework Statement Why is the following set of electric and magnetic fields invalid? ##E(x, y, z, t)= E_0 \sin{(kz-wt)} \hat{i}## ##B(x, y, z, t) = B_0 \sin{(kz+wt)} \hat{j}##Homework EquationsThe Attempt at a Solution So, I understand that either both should have (kz-wt) or both should have...

I've gotten so many different answers off the internet on whether the magnetic field is conservative or nonconservative using the three requirements stated here. The part at the bottom of that article doesn't really clear things up for me. Thanks!

I mean physicists when they have to create a field they draw it with the same direction of the force, (gravitational, electric for example) i know that the magnetic field acts only on moving charges and i also know that the force is a relativistic effect of lorentz contraction, but why creating...

Homework Statement [/B]Homework Equations B = u0*I / 2pi * r that's the only equation relevant in this problem U0 is a constant wth a value of : 4pi x10^-7 The Attempt at a Solution okay so what i did was use the equation above and find the magnetic field (B) for I1 I3 and the x and y...

It is common to calculate Berry phases for quantum systems in, for example, a magnetic field. In this case we compute the Berry phase ##\gamma## using $$\gamma[C] = i\oint_C \! \langle n,t| \left( \vec{\nabla}_R |n,t\rangle \right)\,\cdot{d\vec{R}} \,$$ where ##R## parametrizes the cyclic...

Homework Statement Metal cylinder of radius a has the z-axis as its symmetry. It has magnetic field at any point P as: $$B[x,y,z] = \frac{1}{2} \mu_0 J_z [-ye_x + xe_y]$$ A cylindrical hole of radius b which is displaced from the cylinder's axis by d in the x direction. The magnetic field...

Homework Statement A coil with 140 turns, a radius of 5.2 cm, and a resistance of 11.0 Ω surrounds a solenoid with 200 turns/cm and a radius of 4.5 cm. The current in the solenoid changes at a constant rate from 0 A to 2.0 A in 0.10 s. Calculate the magnitude and direction of the induced...

Homework Statement A cylindrical conductor of radius ##a## has a hole of radius ##b## and there is a current ##i## uniformly spread inside the conductor. Calculate the magnetic energy of the conductor. Homework Equations $$U_{m}=\int_{Volume} \frac{B^2}{2 \mu_0} dV$$ The Attempt at a...

So i know that magnetic field lines are closed, in an electromagnetc wave how can be these lines closed? i cannot picture this in my head

Homework Statement A rectangular bobbin of 50 turns is got sides of 5.00 and 8.00 cm and carries a current of 1.75 A. I'ts orientated as shown in figure 37º and turns around z axis. Determine the potential energy of the bobbin when its inside a uniform magnetic field of 1.5T in the y-axis...