Magnetism Definition and 974 Threads

Hello! Homework Statement This is a problem with magnetism and mechanical work. Two magnets are facing each other with opposite poles, where the space between them is called x. The left magnet is beeing hold still, and the right magnet moved. The space between them increases from 2 to 7...

I was just wondering; What would happen if a Halbach array of magnets were placed just beneath the heat shield on a reentry vehicle? The plasma produced by reentry is, essentially, charged particles moving at high speed. Would a Halbach array magnetically levitate the reentry vehicle away...

Homework Statement The preceding problem was an artificial model for the charging capacitor, designed to avoid complications associated with the current spreading out over the surface of the plates. For a more realistic model, imagine thin wires that connect to the centres of the plates (see...

Homework Statement Point P is midway between two long parallel straight wires that run north-south in a horizontal plane. The distance between the wires is 1 cm. Each wire carries a current of 1 A toward the north. a) find the magnitidue and direction of the magnetic field at point P...

I have a pair of scissors. The blade is about 1.5 cm wide on one end (near the handle), and it tapers down to nothing after about 7-8cm. The blades are about 3mm in thickness. It's been magnetized, meaning, I guess, I've stuck a magnet on it a few times. I'm exactly sure how or why there is...

I'm a little confused about "voltage". We learned that voltage is somewhat similar to electric field: a way to refer to the potential energy of a charge A when put near charge B without actually knowing the charge of charge A. That made sense to me, but then suddenly in class (this is college...

I was wondering if we can use magnets to spin items in a way that they will continuously spin for a very long time with good conditions of the material used. By this I mean it can spin for a very long time without being touched or relying on any other thing to help it spin. other then the pull...

Homework Statement Find the average potential over a spherical surface of radius R due to a point charge q located inside. Show that in general: (EQ 1 below), where Vcenter is the potential at the center due to all external charges and Qenc is the total enclosed charge Homework Equations...

Hello everybody: I've got a few questions that I could not find answers to, so perhaps someone on this forum can help me out: 1) If a magnet loses it's magnetism when heated, and magnetism is caused when electrons are aligned in a specific way, how come the Earth's magnetic field is...

I have few questions about magnetism: Magnetism: Is the current in permanent magnets the result of electrons orbiting the magnets atoms? Do electrons have to be in specific orbitals to create magnetism? Can the magnetism created by an electron's spin be understood through special relativity...

This is something I can't get my head around, and hopefully someone here could help. Say you have a fixed permanent magnet (not an electromagnet), and you place a metallic object with mass nearby. The object will begin to accelerate toward the magnet due to magnetic force. At the moment...

Hi, So my former knowledge of electricity and its movements made me understand that only electrons move from the negative electrode to the positive and then through the wires back into the battery. But as I am reading from my textbook (about capacitors) I am starting to feel that even protons...

Ok, I have two questions: First of all, are there any instances in which a magnet (not an electromagnet) will remain magnetized forever? I know that some magnets do lost their magnetivity Secondly, if the above is true then consider the following theoretical scenario: Imagine a large Iron...

Thunder in relation to Earth's core. Is there a relation to how the Earth's core revolves and circulates regarding thunder? What if one would track the amount of energy beeing surged and what direction it might seem to be heading, if has a direction? Is there a inderect link between lightning...

Hello, I was hoping if any of you could help me with this problem. It's one of the many I have for my homework assignment. A long straight wire carries a current i. A particle having a positive charge q and mass m kept at a distance x from the wire is projected towards it with a speed u...

A conductor suspended by two flexible wires as shown in Figure P19.18 has a mass per unit length of 0.0500 kg/m. Figure P19.18 (The picture is an attachment) What current must exist in the conductor for the tension in the supporting wires to be zero when the magnetic field is 3.70 T into...

what must change? the speed of the current or the direction of it? thanks

Hi I read in some book that current creates magnetism. but what current? DC or AC currents? steady or changing currents? transformers works with ac currents and not with dc. this is confusing me... Thanks

I understand that magnetic force is a relativistic effect of electric force. Is there a force which is the relativistic effect of gravitational force? If a stationary observer sees 2 electrically charged particles moving parallel to each other at the same very high speed relative to himself...

Homework Statement a single square loop of high resistivity wire ( rho = 10^-6 ohm-meters) is placed in a constant magnetic field B of 0.3 Teslas and oriented so that the axis of rotation of the loop is perpendicular to B and in the plane of the loop. the loop rotates with an angular frequency...

Hi, While studying my E&M course I asked my myself the question: why do the sides of magnets of same pole repel and opposites poles attract? I just can't manage to answer that question. I'm sure there is a very simple answer... Can someone help me with this?

Point charges w/velocity have a magnetic field. How does an uncharged capacitor slow the point charges to zero velocity? Shouldn't elastic collisions with other point charges or atoms predominate, followed by inelastic collisions that convert point charge kinetic energy to thermal energy?

ive been hearing about this course in the community college i attend and from what I've heard is that this is the hardest lower division physics course that most people take. I am a civil engineering major and the people I've talked to are also engineering majors. any advice for those who have...

Homework Statement An electron has a velocity of 2.00x10^6 m/s perpendicular to a magnetic field of 3.3T. What force does the electron experience? Homework Equations The Attempt at a Solution F=qvB q=1.6x10^-19 (the charge of an electron) V=2.00x10^6 B=3.3...

Hi, I have a research question focusing on the historical development of the telephone. However, I have to write it with emphasis it's dependence principles of magnetism. So far, I have not found anything to relate the two topics. I also must include 1. a reference to at least one person who...

There's a principle that the electric field is stronger/more intense at the most pointed parts of a charged, non-uniform conductor. Does this principle also apply to magnets? I.e. if we have a non-uniform magnet, is the magnetism density (sorry for the lack of a more scientific word) greater...

Hello I have these two questions on electricity and magnetism which I don't understand very well these are: (Q1) If a closed surface encloses no charge, and electric field lines cross the surface. (Q2) Under what conditions can coloumb's law be used to find the electric field strength...

Like the earth, do other planets have magnetism?

http://psi.phys.wits.ac.za/teaching/Connell/phys284/2005/lecture-01/lecture_01/node13.html But what about induced current? My brain is full now, can't think.hehe: http://www.physics.uoguelph.ca/applets/Intro_physics/kisalev/java/indcur/index.html

If you take a screwdriver for example, and hit it a few times near the tip with a hammer or something hard; why does the screwdriver become magnetic? I was shown someone doing this, and shortly afterwards it was able to attract nails or screws around.

suppose you have a solenoid with hollow core connected to a galvanometer. On one side you have a S-N magnet (ie. the N pole is nearer to the solenoid). On the other side you have a N-S magnet( ie. S pole is nearer to solenoid). ie. [S - N] [Solenoid] [N - S] Both magnets are...

Does conservation of energy apply to magnetism? and Do magnets ever "wear" out. Do they ever lose their magnetism?

Homework Statement http://img231.imageshack.us/img231/5296/physicspd2.jpg Homework Equations none really. The Attempt at a Solution 1. I think that the two outside magnets would attach to the middle one and their eventual velocities and accelerations would equal 0 but that...

Magnetism! Help! can someone please explain the hand rule thing to me...i am dead lost when teacher is explaining it. All i know is that your thumb is N and the bottom of your hand is S...please help!

Homework Statement Two infinitely-long lines of charge run parallel to the z-axis. One has a positive uniform charge per unit length, [lambda]>0, and goes through the x y plane at x=0, y=d/2. The other has a negative uniform charge per unit length, -[lambda], and goes through x=0, y=-d/2...

Homework Statement a) You have two electrically neutral metal cylinders that exert strong attractive forces on each other. You have no other metal objects. Can you determine if both of the cylinders are magnets, or if one is a magnet and the other just a piece of iron? If so, how? If not, why...

http://sci-toys.com/attention/2007/05/einstein-points-way.html According to the author, magnetism is an implication of Einstein's relativity. Is it true? His arguments sound reasonable, though.

Can anyone check if I answered these questions correctly? Thanks a bunch! 1. The N pole of a bar magnet is pointed in along the axis of a horizontal, continuous coil of wire. When the magnet is quickly roated about a vertical axis until the opposite end of the madnet points into the coil...

I will probably be taking both CM I/II and E&M I/II before I graduate, but I'm wondering is it a bad idea to take E&M before taking CM? I don't think I can take both at the same time this coming year so I have to pick just one.

Homework Statement Purcell 3.3: In the field of a point charge over a plane, if you follow a field line that starts at the point charge in a horizontal direction, that is, parallel to the plane, where does it meet the surface of the conductor? Homework Equations The problem 'hint' is...

Light is the result of an electron moving to a lower energy state, giving off a photon a particular wavelength in the electromagnetic spectrum. Current is the movement of electrons which induces a magnetic field. A magnetic field can create current by moving charges. Is there a relation...

Say we have two electromagnet A and B a light year apart from each other. Someone turn on A and a magnetic field is created and propagate at c toward B. It takes a year for the mag field from A to arrive B, B is turned on just before A's field arrive. B's field made to be opposite from A and...

Hello. I am a new poster; I hope I am correctly observing the forum rules. I have a slightly philosophical question about magnetism. It seems to be very simple, but I am struggling to find myself a convincing answer. Here it is: - - - If you place a piece of magnetically susceptible...

Hopefully I am posting in the correct forum, but was reading through Cahill's 'Physics 12 for Western Australia' (2nd Edition) and reached chapter 3, regarding magnets and electricity. There was one paragraph which confused me, and seeing as the school year has not started yet, there is no...

Hi everyone! As I understand it, magnetism can be explained by special relativity when charges are moving - length contraction in different frames of reference leads to coulomb forces between the charges in these frames. But how does magnetism in a permanent magnet arise? Are there...

I'm completely confused because of a previous post on Newtons second law and magnetism! Can someone help me to find a connecting or a superior explanation for the magnetic field as it appears in its the 2 forms? 1.) In some solid due to spin alignment. 2a.) In a cirque current flow. 2b.)...

Homework Statement A high voltage power line carries a current of 110 A at a location where the Earth's magnetic field has a magnitude of .59 G and points to the north, 72 degrees below the horizontal. find the direction and magnitude of the magnetic force exerted on a 250-m lengh of wire if...

[SOLVED] Magnetism question Homework Statement A proton, a deuteron and an alpha particle with the same kinetic energies enter a region of uniform magnetic field, moving at right angles to B. Compare the radii of their circular paths.Homework Equations v = qBR / m The Attempt at a Solution...

Question: http://web.ics.purdue.edu/~yeo/phys1.jpg Formula: (Gauss's Law for Magnetism) Line integral of[B dot nhat(perpendicular unit vector) * deltaA] = 0 The Attempt at a Solution So, if there is a bar magnet inside, the side arrows are pointing in the wrong direction, so I ruled...

Hi everyone, first post. I am curious to know how magnetism from a solar body differs at its equator. does it differ at all? Since the North and South are theoretically maximum points in the magnetic loop, at the very equator of their relationship this would be an inverse of that maximum...