Magnetic field Definition and 1000 Threads

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...

Homework Statement [/B] Homework EquationsThe Attempt at a Solution Solution for Q1: Solution for Q2: Solution for Q3: Are they correct?

Hi, I would appreciate it if someone explains the difference between these two phases regarding a coil rotates in a uniform magnetic field. 1. The rate with which the coil intercepts the lines of magnetic field in the dynamo is maximum when the plane of the coil is parallel to the lines of the...

muons mean lifetime of 2.2 µs muons in a strong gravitational field or traveling at relativistic speeds experience time dilation would a muon in a strong magnetic field, say near a magnetar experience additional time dilation more than a muon in an non-magnetic field with the same...

Is the spin of a photon pointing in the same direction as the magnetic field of the photon?

Homework Statement Uniform magnetic field ##= Bt## exist in cylindrical region of radius ##R## is pointing into the plane of figure (as shown in figure). A frictionless groove of length ##L## is fixed symmetrically from the centre O at a distance of ##\frac{L}{2}## .A charged particle of mass...

Hello, and thanks in advance for taking a look at my question. Generally, I am trying to make a railgun force model. Since railguns depend on the magnetic field created around the rails (and the resulting Lorentz force) I need to model the magnetic field created by the current that flows...

Hello Today we did a lab and one of the activities was having a compass underneath a wire while the current was off. The wire was straight so that it was directly aligned to be with the needle of the compass. One the current was flowing, the compass arranged itself in that it was not exactly 90...

Let us consider the following thought experiment. There is a magnetic field in free space produced by a steady current, hence solution of the (magnetostatic) Ampere's law Curl H = J. There is also a material with some parameters ε and μ and no currents, where the Ampere's law is Curl H = 0...

If I have some arbitrary conductor moving through a (nonuniform) magnetic field \mathbf{B}(\mathbf{r}), would the induced field in the frame of the conductor be something like: \mathbf{B}_{IND}(\mathbf{r}) = T \mathbf{B}(\mathbf{r}) where T is some diagonal matrix whose entries are related to...

In the class our prof said, Sun changes its magnetic poles in every 11 year.And when changes the black spots on the sun increases Is this true ? Also she said Sun's cosmic radiation waves destroyes the upper atmosphere of earth.It was something like this.I don't quite remember.Actually thata...

I'm familiar with the relationship \nabla\cdot\frac{\hat{r}}{r^2}=4\pi\delta(r) in classical electromagnetism, where \hat{r} is the separation unit vector, that is, the field vector minus the source vector. This is result can be motivated by applying the divergence theorem to a single point...

Homework Statement Particles of mass ##m## and charge ##q## are initially traveling in a beam along the ##z## direction with speed ##v## when they enter a long magnetic quadrupole lens, where there is no E-field and the magnetic flux density is ##B = Ay\hat{i} + Ax\hat{j}##, and where A is a...

Homework Statement A 470-turn solenoid having a length of 25cm and a diameter of 10cm carries current of 0.29A. Calculate the magnitude of the magnetic field inside the solenoid. Homework Equations ##B=μ_0nI## where ##n=\frac N L##...

Hi, I would like to create an electric or magnetic pulses in an open ended cone, sphere or a tube. The pulse would have to be generated in such a way so that it is not actually connected with the container in any way (ie. it can't be a device in the center of the container which generates the...

Homework Statement Show how the given physical magnetic field is consistent with a monochromatic plane wave solution to Maxwell equation Homework Equations [/B] Physical: > Bphys(t) = B0 sin (2πft) ex Maxwells: > B = iB0 exp[i(kz − ωt)] ex.The Attempt at a Solution I know that field is the...

Does the moon pass through the Earth's magnetic field?? If so how strong would the field be?? Would it be strong enough to possibly generate a current throw some kind of conductor?? And always thank you for anyone that take the time to answer my questions.

1. The problem statement Relevant equations: I am confused. When dealing with Ampères law: dl is supposed to be the length element? Like when we have Gauss' law for electric fields and we use a circular Gaussian surface, we have E(4πr^2)=Qenclosed/ε So in this case, when we have a circular...

Homework Statement ##l/l_0=100## ##S=3 (cm)^2## ##B_r=200μ_0H_c=2mT## ##R=10Ω## No current runs through the feromagnetic core. Calculate the charge ##q## that goes through ##R## from the moment in the diagram to the moment it is removed from the core. Homework Equations 3. The Attempt at a...

Howdy, So, I'm curious, is there a general relationship between current input into an electromagnetic and the magnetic field that it generates in space? The trivial example is wrapping a wire around a rod, then sending a current through it which causes a magnetic field. My set up is a simple...

Homework Statement Homework Equations μ0 In,e = ∫B⋅ds The Attempt at a Solution I really don't how to approach this question at all. Do you have to integrate counterclockwise around the loop every time? If the field was decreasing as y decreased, would you integrate CW or is it still CCW...

Homework Statement 2. Homework Equations FB = ∫I ds×B The Attempt at a Solution My first guess was that it would not move at all. I understand that there is an induced magnetic field in the opposite direction but wouldn't the induced field produce a current counterclockwise, which, since...

Homework Statement You're an electrical engineer designing an alternator (the generator that charges a car's battery). Mechanical engineers specify a 10-cm-diameter rotating coil, and you determine that you can fit 250 turns in this coil. To charge a 12-Vbattery, you need a peak output of 16 V...

Hello All, Briefly on the exposition; I'm an undergraduate assistant to a professor. We contribute to the Muon g-2 experiment in Fermilab, designing and optimizing the magnetic-measurement equipment. As you might imagine I utilize the Fourier Transform often to analyze data. The data I'm...

When you run current through a circle formed wire it generates a magnetic field. Will this field affect the current in the wire that generates it? I mean if it does wouldn't the calculations for the created magnetic field be rather circular? The magnetic field depends on the current which in...

Homework Statement Find the magnetic field of a uniformly magnetized sphere. (This is an example in my book, I have underlined what I am having trouble understanding down below.) Homework Equations $$\vec{J}_b = \nabla \times \vec{M}$$ $$\vec{K}_b = \vec{M}\times \hat{n}$$ $$\vec{A}(\vec{r}) =...

When a charge is rest w.r.t me no magnetic field is produced but when it moves w.r.t me then there exists a magnetic field, how?

Imagine we take a vertical, infinite wire and we let electric current pass through. The charges create magnetic field all around the wire. Now if we introduce an electron in the magnetic field, it will have a circular motion around the wire. The Lorentz force is not conservative, this means...

I have a question which puzzled me when I was reading up about auroras. When talking about the interaction of the solar wind and the Earth's magnetic field, the book said that "particles are accelerated along magnetic field lines towards the earth" That didn’t sound quite right, as I was taught...

Homework Statement In a lab that I did in Physics we calculated the magnetic field of a solenoid while constantly increasing the number of time the wire was wrapped around the electromagnet. After I obtained all the values, plotted it in a graph and found the line of best fit, the slope came...

first off i want to apologize if my questions seem elementary, but if you can please help that would be great i would like to know what the Tesla strength of the Suns pole is. again sorry if my idea is dumb but please if you can help please do, i want to solve for I in the magnetic field...

Hello, Please consider this diagram: From the diagram, we can see there are two forces. One: The Lorentz Force (qvB). Using the RHR, we can see that there is a force pushing north (up) to cause the separation of charges in the sliding conductor to establish the current in the loop. Two...

EDIT: While going over the data again I noticed the sensor was giving us the data in µT, I'm editing the data I wrote to reflect this change of x10^-3 in magnitude. 1. Homework Statement On lab class we are exploring the relation of a magnetic field on a solenoid (B) with its number of turns...

Lets suppose that I have a magnetic dipole moment at (0,0,0) pointing to the Z axis, and in the position (X,Y,Z) in the space, I have a Hydrogen atom, I would like to know the exact interaction between the magnetic field created by the magnetic dipole moment in (0,0,0) and the magnetic fields of...

Homework Statement Two circular coils of diameter 30.0 cm are parallel to each other and have their centers along the same line L but separated by 22.0 cm. When an experimenter views the coils along L, the coil closer to her carries a clockwise current of 2.50 A. Find the magnitude and sense...

I am currently studying Faraday's law and electromagnets and in class we were told that if you had a coil and say a bar magnet was passed through it the faster the magnetic field was applied to the coil the greater the induced voltage or emf would be. I do not understand why the speed would...

Homework Statement A long, straight wire lies along the z−axis and carries a 4.20 −A current in the +z−direction. Find the magnetic field (magnitude and direction) produced at the following points by a 0.400 −mm segment of the wire centered at the origin. Homework Equations ## \vec B ## = 2...

Hello, I'm new in the forum. I was just wondering, if the brain acts by sending electrical impulse, then the presence of a magnetic field should affect its motion right? Anyone knows how that affects its function? Depending of the answer I would have a couple of questions. Thank you

Homework Statement A single-turn wire loop produces a magnetic field of 41.2 μT at its center, and 5.15 nT on its axis, at 20.0 cm from the loop center. Find loop raidus and current. Homework Equations F = qv x BThe Attempt at a Solution I tried to use the above equation, but could not figure...

hi i was wonder as to why when an solonid is placed with a current within and magnet there's a an rotational force. why is it that he difrence in strength of magnetic field created results in an rotation many thanks Ewen

A long horizontal wire carries 22.0A of current due north. What is the net magnetic field 20.0 cm due west of the wire if the Earth's field there points downward, 40 degrees below the horizontal, and has magnitude 5.0 E-5 T? My approach: 1. Drew north to the right and the wire lying flat, with...

Hi all, the question is in regards to magnetic fields in a wire. Please refer to illustration below to understand my question. (https://www.imageupload.co.uk/image/B9f1) As you can see in Picture 3 two wires parallel to each other will attract each other if the current is going in the same...

Hi All, what is the reason why very close to an electromagnetic source (Fresnel Region), the wave impedance Z0 in free space for electric field and magnetic field is not the same? Z0 for magnetic field increases and for electric field decreases by increasing the distance from the source...

Hi the difference between a loop antenna and a magnetic probe (B-Probe) is only that the loop antenna works in far field and B-Probe works in near field? The standard features of magnetic antenna (antenna factor, impedance matching, radiation patterns, efficiency, ecc) have the same definition...

I'm having some confusion about the creation of magnetic field lines. How I understand it so far, is that a magnetic field is basically an electric field viewed from a relative point. I don't have a great understanding so far, as I just started to learn about it, but I've learned that objects...

Homework Statement A beam of doubly ionized particles (i.e., twice the elementary charge) is accelerated across a potential difference of 2000 V in a mass spectrometer. They are then passed perpendicularly through a magnetic field of 0.085 T resulting in a radius of curvature 12.5 cm. Calculate...

Homework Statement I need to identify which class bar 1 and bar 2 belong in based on observed attraction/repulsion. Then I need to determine if the end of 2A would attract, repel, or niether to end 3A. EDIT: Could not get this image in the post due to security reason apparently so here is the...

Does a rotating magnetic field possesses angular momentum in the direction of rotation? I suppose this comes down to a broad question about the physical nature of fields in general. I love the Einstein-de Haas effect, where an iron core spins in the opposite direction of the induced spin...

Homework Statement The figure shows a 10-cm diameter loop in three different magnetic fields. The loop's resistance is 0.10 Ω. For each case, determine the induced emf, the induced current, and the direction of the current. Homework Equations Faraday's Law: εinduced= - (ΔΦb/Δt) = - A ⋅ ΔB...