Magnetism Definition and 974 Threads

Hi, I'm not able to understand how reversing Field terminals will help build magnetic flux in dc shunt generator Have drawn diagrams below. In 1st case machine doesn't generate as the flux opposes residual flux, so I reverse F1, F2 and draw below diagram... But in second case the direction of...

I'm not if this is the right place for this, so mods can feel free to move this. I'm a part-time student going into my second semester of 300 level physics class. This past semester I oscillated between feeling just fine and questioning whether physics was right for me (usually around test...

Hii... can someone explain to me why the electromagnetic wire doesn't experience any motor effect when in parallel to the magnetic field of the permanent magnet? And why does a thicker wire increases the catapult effect? Ty in advance :)

I have read that, while copper is not magnetic per se, if we have a strong enough magnet, it can interact with copper. This ties in with the fact that all matter can be magnetic if you have a strong enough magnetic field. But I am interested, how strong must the magnet be to interact with such...

In my experiment, I intended to find out how the change in the bar magnet drop height from solenoid affected the emf induced in the solenoid, however, I am unable to come up with an equation that shows a relationship between the two variables. I have thought of Biot-Savart law, but I do not...

The sources I've looked at claim the magnetic field is present because there are still some electrons in the neutron star. Here is how I understand their reasoning: a star's radius significantly decreases when it collapses into a neutron star, ultimately decreasing its moment of inertia. In...

Homework Statement It is shown in more advanced courses that charged particles in circular orbits radiate electromagnetic waves, called cyclotron radiation. As a result, a particle undergoing cyclotron motion with speed v is actually losing kinetic energy at the rate $$\frac{dK}{dt} = -...

When a test charge stands next to a wire, there are coulomb forces between the test charge and the protons of the wire. 1: When the test charge starts to move, the Coulomb forces stays the same, because distances from test charge to protons stay the same. There is no magnetism in this case...

How would you calculate the induced magnetic field B at some distance R from a bar magnet, given the magnetic moment of a magnet? (In general)

My physics teacher said that the northern lights are the product of charged particles coming from the sun and interactign with our atmosphere. I believe he said that these are deflected by Earth's magnetic field and directed towards the North and South poles. When I look at pictures on this...

Homework Statement Hi! A long, straight, current-carrying wire is placed between a pair of magnets as shown. What is the direction of the force on the wire? Homework Equations Fleming's hand rules The Attempt at a Solution I used the Flemings right hand rule but that gives me that the force...

The only way for me to move 1200 degree steel is with a magnet. The magnet loses its magnetism at 800 degrees, though, causing some pieces to fall and potentially injure people. Is there a way to electrically boost the magnetism of an existing magnet, apply an additional field to the magnet...

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...

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...

Hi guys, Disclaimer: not a physicist (I wish I was that brainy) Quick question regarding a speculative architecture project I am undertaking; In the completely hypothetical event of a huge, otherworldly solar flare super-charging the Earth's ionosphere beyond anything we have ever recorded...

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...

Hi in every theoretical explanation of any kind of DC motor there's always a split ring commutator and two brushes like in the following pic then when it comes to my motorbike/car starter motor rebuild the real thing in practice is different- see the following pic with four carbon brushes- two...

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...

I was wondering if diamagnetism can be created electrically or does the material have to be diamagnetic in nature?

I've just started looking into MHD and am a bit confused.ive read the threads on moving charges,and special relativity. So I am thinking of this thought experiment.. we construct a test area shielded from all extraneous magnetic fields, in this area we have a torus shaped pipe and pump a...

Hi. I have three questionns to ask. A very close point on the axis foo a current carrying circular coil (x<<<R) of radius R, the value of magnetic field decreases by a fraction of 5% with respect to the center value. The position of the point from the center of the coil is: (a) R/10^1/2 (b)...

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...

Using special relativistic calculation it can be showed that magnetism is a result of electric charges in motion. using the same argument, why can't we find a magnetic force like thing for gravity?

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...

My thoughts are concerning an infinite sheet carrying current in a direction. I wish to induce a unidirectional electric field outside of the sheet via induction. My ideas were that if the current was changed linearly in a sawtooth fashion, then I would achieve the induced electric field in...

Hey guys, recently I have conducted an experiment investigating the effect of temperature (K) against magnetism (mT). I have found two formulas and understand that they are for both linear and non linear relationships but why does the function change from linear?

Consider a waveguide with axis parallel to axis ##z##. Using cartesian coordinates the fields inside the waveguide can be written as Where ##\alpha## is the wavenumber and ##k=\frac{\omega}{c}## . The maxwell equations ##\nabla \times E=-\frac{\partial B}{\partial t}## and ##\nabla \times...

Homework Statement I came across a pretty interesting question that asks for magnetic flux density (B-field) on the axis of the equilateral triangle. This axis is meant to be perpendicular to triangle's surface passing through its centroid. Assuming that a triangle has sides denoted ##a## and...

I'm new to the concept of diamagnetism, but it seems very fascinating, and I'd like to try a simple experiment. Say I wanted to repel a small piece of lead (or copper, both are readily available to me) about 3.5 grams, how strong of a magnet would I need? Could I just use small neodymium magnets...

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...

Homework Statement Homework EquationsThe Attempt at a Solution Maybe the proton will move directly upwards? because that is the opposite to the direction of the conventional current.

HI! I'm a student, this question appeared in one of the old tests. I though I had it solved but apparently I must have missed somewhere. Could someone please at least hint me where I went wrong? Homework Statement Thin wire is wound into circular frame with radius ## r = 0.05m ## which...

Homework Statement A current carrying rod is held horizontally between the poles of a magnet by a magnetic force. magnet-current (into the page) -magnet determine which side is the north pole of the magnet? Homework EquationsThe Attempt at a Solution If I use the right hand rule, then the...

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...

Two long, parallel wires are separated by a distance of 1.0m. The current in each wire is 1.0A. What is the magnitude of the force on 1.0 m length of each wire? Help~ Thanks a lot

During an intense lightning storm which led to a tornado warning, I saw something in my yard which no one has yet explained. There was ordinary lightning near the ground about 30 feet away. Then I saw the whole front yard filled with fine vertical lines, evenly spaced, maybe a foot or less...

Homework Statement current in wire is in east to west direction.direction of magneetic field below the line Homework Equations right hand thumb rule The Attempt at a Solution i used the right hand thumb rule to find the direction of magnetic field but the magnetic field comes out in in the...

If one was to create an array of X amount of mirrors tracking the sun and shining on a targeted spot in the sky to create ions at specific elevations similar to a ladder, could this cause an ion column to create a continuous charge of energy from the upper atmosphere to hit the ground? Lets...

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...

Hi, Quick description of the problem at hand: spherical perfect conductor around the origin with radius a, spherical shell (with radius b) around it made of a material with given magnetic permeability bigger than 1. Uniform Magnetic field in the area. The solution I am looking at (which I won't...

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...

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?

Hey everyone, I have been doing some research in regards to floating an object, and possibly have it rotate. I am thinking magnetism is the way to accomplish this, but if anyone else knows another method I would love to hear it. I created a simple diagram on what I am trying to accomplish...

I am trying to calculate the forces (in Newtons) between a permanent magnet, and an electromagnet. All I can find is interactions between permanent magnets, electromagnets, but never both and it is getting really confusing for me to do the calculations. So basically, if I have a permanent...

There is a similar thought experiment I imagined to help me begin to understand the Bell's spaceship paradox: Consider two positively charged spheres, placed side-by-side inside a frame S' with a string stretched to the point where it balances the repulsive electrostatic force between them. For...

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...

Whenever I've encountered measuring magnetic fields with magnetometers, they've typically been very large magnetic fields (up to a few T). Magnetic fields fall off rapidly with distance and so I generally figured that measuring weak fields at distances on the order of cm (let alone m) was very...

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 Two thin glass rods are placed side by side 4.70 cm apart as shown in the diagram below. They are each 11.3 cm long and are uniformly charged to +10.4 nC . Answer the questions below regarding the electric field along a line which is drawn through the middle of the two glass...