Magnetic Definition and 1000 Threads

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?

Can anyone please explain me the physical significance of these concepts?? Electric permittivity, Magnetic Permeability & suceptibility

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...

Homework Statement Consider a conductor loop which rotates about the y-axis with angular velocity w. The positive y-axis is directed into the paper, the x-axis to the right and the z-axis upwards. There is an inhomogeneous magnetic field along the positive x-axis. Calculate the magnetic flux...

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 =...

Hello all. Me and some friends are building a coil cannon, and we've been doing some calculations [I know its unecessary but... well, we're physicists! (well, physics students...)]. But we got stuck. How to calculate the force acting on a steel bar (or some other ferromagnetic material, maybe...

I learned this in college 48 years go, problem is I have forgotten more than I ever knew. I know the answer is not very hard like 20 degrees but the internet is pissing me off. I looked this up and I get FAKE stuff like advertisements. Novels with many pages to read that never tell the...

Consider two thin and long, single layered identical solenoids with same DC in them, positioned coaxially. I'm trying to calculate the magnetic force on each solenoid, when there are identical magnetic cores inside them. As seen in below, I have the general approximation to the force between...

Homework Statement Homework EquationsThe Attempt at a Solution Is it A?

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 A rectangular loop of wire, L = 28.8 cm and W = 15.2 cm, carries a I1 = 2.02 A current and lies in a plane (d = 11.0 cm), which also contains a very long straight wire carrying a I2 = 12.7 A current as shown in the figure below. Homework Equations F=uo*i1*i2*l/perpindicular...

(1) Magnetic force acting on charge moving in magnetic field is given by, F = qvBsinθ...F ∝ v This means that if moving charge particle has more velocity then more magnetic force will act on it. Due to more magnetic force the direction of velocity changes rapidly and it will move on the...

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...

so i am literally one step away from producing a floating skateboard powered by permanent magnets, so here's what i wanted to check, to make sure I haven't missed anything obvious vertical lift achieved by using vertical repelling fields rotational motion is controlled by counterbalancing the...

Hi, I can't find my inductance calculations book. Say that you were considering magnetic flux linkage more from a geometric perspective: -Does the mutual coupling coefficient for a series of coils all on the same steel core add up to a maximum total of ~1? Because I tried simulating a three...

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...

I want to record the displacement of a small magnetic ball moving sideways across the face of the sensor. I've had a close look at AMS's catalog of magnetic position sensors and I'm not sure how to choose one. If I'm working with a movement range of <5mm and want a resolution of 5-10μm, and...

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

In a transformer, the primary coil has a current running through it which creates a magnetic field. Then this field induces a current in the secondary coil. That induced current creates a magnetic field exactly opposite the inducing magnetic field. This might be an obvious question, but that...

What is the four-vector related to electric and magnetic dipole moment?

Hi folk Is there a method to calculate the magnetic energy stored in a permanent magnet ? Thanks for help

Homework Statement A proton moves with constant velocity in a certain region of gravity-free space.Which one of the following conclusions is valid? A)There must be no electric field or magnetic fields in the region. B)There could be an electric field without any magnetic field. C)There could be...

I've posted this here because I think it might be related to the absoluteness of acceleration and rotation. I've been educating myself on the Faraday Disk and was very surprised by one aspect of it. If we have a solid metal disk mounted on a shaft with two electrical brushes contacting the...

Homework Statement Homework EquationsThe Attempt at a Solution i have done the first two parts but the third part confuses me i am assuming the current is flowing in the z direction then current is parallel to the magnetic field then why would there be a force acting on it ?[/B]

The equation needs to describe the force between two magnets and should relate to distance, angular frequency, angular acceleration, and torque. I need to find this equation for a research project, but I just can't figure it out and I can't find it online. (I'm new to this website so if this is...

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...

I have this question which I need to solve . But I am unable to. Suppose I have a current ring of radius R and current I (constant). at a distance x from the centre of the ring, I have a iron disk (radius r and thickness t) present in the plane of the ring. This disk will be attracted to the...

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...

Hi, I have a problem with the fomular u=m·B and u=B^2/4pi Since I want to calculate how many magnetic energy on a solenoid, I couldn't decide which fomular should I use.

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}...

Is it possible to create a hollow magnetic sphere?

Magnetic braking is a theory explains the loss of stellar angular momentum and is used extensively to describe the given rotation stars. However, on a smaller and more directly observable level, when we consider Jupiter's rapid rotation rate of less than ten hours and its accompanying powerful...

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...

my textbook says that electrons have a basic characteristic of magnetism just like charge and mass. this magnetic property in some materials adds up to result in a permanent magnet and in some others nullifies each other. how does it really occur? moreover if electrons hav magnetic properties...

Hi, I saw this video and I can't explain why the magnet is propelled to the end of the coil with such a huge force. Can someone explain it in clear terms. I also tried to use Flemings left hand (or right hand) rule but it did not give me a satisfactory answer. Thanks, SM

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?

Homework Statement Homework Equations f = q.v.B.sin tetha I = q/t = v/R The Attempt at a Solution (1) q =a.b.n.v.t is it right? (2) I = q/t = abnvt/t = abnv is it right? (3)F = q.v.B is it right? (4) ? (5) ? is it right?

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.