Magnet Definition and 868 Threads

Homework Statement A magnet is dropped towards a loop of copper .the acceleration of magnet will be ? Homework Equations The Attempt at a Solution less than g ,because copper will oppose the relevant pole(im not sure why?)

Homework Statement I'm trying to figure out and explanation as to why a strong magnet drops so slowly through a non-magnetic but conducting Cu tube. The attached diagram shows the original B field, induced Eddy currents, and secondary B field as a result of those Eddy currents, but I can't...

Lets assume that liquid superconductors exist. Now I place a magnet above a pool of the liquid. Now will the surface of the liquid remain level or will it appear to have dent in it. I am not sure I kind of back and forth in my head.

Dear Experts Could you tell me does putting magnets on fridge doors consume more electricity or no effect? Thanks. Regards Ramone

Correct me if I'm wrong about anything. I've browsed here many times, but this is my first post. I was thinking about Prince Rupert's Drop (http://en.wikipedia.org/wiki/Prince_Rupert's_Drop) and I wondered about spherical magnets. Prince Rupert's Drop is able to withstand high magnitudes of...

When we consider a magnet, usually we perceive the field lines to come out of the north pole. But since the poles of a magnet is actually just a man-defined thing, so actually the magnetic field doesn't emerge from the north but it's a constant loop. So when i draw the magnetic field of a bar...

Hi, I need to know how to calculate the power level and pulse width required to revers the polarity of a rod or bar shaped alnico magnet, depending on the width. I also don't know whether to use AC or DC power. I'm prototyping an invention and it needs to be as power efficient as possible.

if you have a magnet that pulls 40lbs of force if you broke that into 2 how much force will each magnet pull. i have some neodymium magnets from hardrives and i want to break them up but i want to know if that's gunna make them lose a lot of force. anyone know the formula for calculating...

Hi a simple question that struck my mind.Let's imagine a ferrite magnet from a old loudspeaker now let's put that magnet on a metal wall , or door , the magnet holds to the metal vertically and any other material put similar would just fall off so t seems to me that the magnet or the magnetic...

The title is pretty self-explanatory. I know the speed of the falling magnet is much slower in a copper pipe, but since the magnetic field moves, is there still some electricity generated in the process, even though the speed isn't great? Thanks!

Hi, this is my first post here. I know that, according to Lenz's law, if you drop a magnet inside a copper tube and let it fall, its movement will cause an induced current, which will slow it down in turn. However, my drawings make me believe that the direction of such current should be one...

Homework Statement Determine the field gradient of a 50-cm-long Stern-Gerlach magnet (d1) that would produce a 1-mm separation at the detector between spin-up and spin-down silver atoms that are emitted from an oven at T=1500. Assume the detector is located 50 cm from the magnet (d2). Note...

Hi, when a perment magnet machine is designed for a particular power but is operated at a much lower power, is it inefficient as with induction machines? Thanks

hey, so let's say i have 2 Neodymium magnets with a pull force of 10 pounds and set them at a position where they repell themselves. so my question is: how can i know in what distance will the top magnet be from the other one? if there's and equation for that or an explanation, please tell...

I am having some trouble understanding why and how the emf changes when a bar magnet is dropped into a solenoid. As the magnet moves down (have not entered the solenoid yet) it experences an increase in magnetic field. As it enters the magnet it experiences an increase in magnetic still until...

So if we can one large not moving magnet and a small magnet that is attracted to the large magnet we know that ( http://en.wikipedia.org/wiki/Magnet ) F = μ qm1 qm2 /(4 pi r^2). Here the small magnet is traveling in a straight line because it is attracted by the large magnet. Where F is...

Problem: 15 MeV electrons enter a bending magnet with a magnetic field of .7 tesla. What is the radius of the path of electrons? Equation: r = mV/Bq B = .7 tesla q = 1.6 x 10^-19 C My problem here is that I don't know how to find the velocity of the electron for this...

I want to determine how large a magnet I need in order to get a given field a certain distance away from the surface. An N48 neodymium magnet has a Bremanence of ~1.47T. How does the physical size of the magnet affect the field a given distance away...

Hi, I'm new here, but it seems there are some pretty intellectual people running around. I was researching magnetorheological fluids, simply because I came across them and thought they were really interesting. I learned that when they are subjected to a magnetic field, the iron particles in...

Suppose a permanent bar-magnet is placed inside a toroid/torus and the toroid is then completed and power applied. How will the magnet move? Will it move?

Hallo everyone, Can a magnet do work on another magnet? (I believe it can. Just wanted to make sure.) What formula's do you use to support you're answer? Finally, I know that magnetic field can not do ANY work on a free charge based on Lorentz force so no need to reference that. Regards, Miyz.

Hi all, I had a thought earlier about magnetic forces. If there's a magnet attached (at rest) to my fridge, then there is a magnetic force on the magnet towards the fridge and vice-versa. This force stops the magnet from falling because of the frictional force between the magnet and the...

How do you go about restoring the magnetic-flux of a horseshoe magnet that has lost all its' magnetic-flux? The magnet was originally weak and was sent to a company to have the magnetisim restored and when returned, all magnetic-flux was gone, as if it had been degaussed.

Homework Statement Determine the direction of the force acting on the current-carrying wire in the magnetic field. Homework Equations Lenz's Law The Attempt at a Solution This problem confuses me as the current is moving in a circular loop. However, I tried to use Lenz's Law and...

First, I am not an electrical engineer - I am a hobbyist building a prototype linear-stlye generator based on an idea I had which, for various reasons, cannot be built with magnets that pass completely inside of coil(s) like most of the ones I have seen described for wave energy capture and...

Say I have a coil that is stationary and I have magnets that move past it in a fashion similar to the example in this video: . What is the optimum orientation of the magnet and coil to induce the most current? I know I will want to optimize the rate of change of magnetic flux through the coil as...

This might be too simple of a question but i am building an electro magnet and breaking down all of the components for sheer practice. when i measure my coils resistance it came to roughly between .9Ω and 1.3Ω... what battery (what voltage should i use to get the most power from my magnet and...

I have heard that when a magnet is moving completely inside a solenoid, there will be no induced emf. Is that true ? Personally, I think even the magnet is moving inside a solenoid with speed v, there will still be induced emf. Assume a magnet is moving inside a solenoid from left to right...

I take it that it would be ok that in the classic demonstration of Lenz's law with the falling magnet, to replace the magnet with some quantum particle of non-zero magnetic moment and make the tubing a solenoid in order to generate a current as the particle fell? Obviously the current would be...

Can we measure the spin of a particle by measuring the force on a Magnet? I wish to consider a modified stern gerlach like apparatus where a Magnet of mass M is attached to a spring. Can we measure Spin of the particle by studying the deflection of the magnet? Even if it is possible, I can...

Hey! I am trying to find a permanent AlNiCo magnet with a magnetic moment of 0.06Am^2. However, most magnet data sheets do not list the magnetic moment of their magnet. Often they list the Magnetic field in Tesla or the moment in Vs*cm. How can I convert this data into the magnetic moment...

As a preface to a different question, it is valid to think of the property of spin of elementary and related particles as basically just tiny magnets, right?

Hi friends. I am so new with Comsol software to design something but I wonder, if it is possible to desing a bending magnet (dipole) and simulate the motions of electrons ? I really would like to do this. Please give me a hand,help me to handle and try to do one together. Best.

So I recently bought a couple of magnets for an experiment and the website lists the pulling force of the magnet as 24 pounds. I am pretty sure there is a relationship between the pull force and the magnetic field. Can someone please help? Thank you!

Hello, I am new to the forums, my name is Brandon. I have just recently graduated high school. I graduated from my physics class with a 97% for the year! yay! But off to my question... I have been thinking of a cool project that involved 4 neodymium magnets and using the repulsion force...

Hello, Please forgive my ignorance. I am not a mechanical engineer or physicist by degree or trade (I am a software engineer). I am well aware that perpetual motion is a violation of conservation, and that (even if it were not a violation) perpetual devices could not perform work. My...

I'd like to make a strong (~0.5 T) solenoidal field with a permanent magnet for a Faraday rotation experiment. If I take an ordinary cylindrical permanent magnet (with an axial field) and drill a hole down the center of it. What's the field deep inside at the center of the hole? Some of the flux...

Pretty straight forward. Whats the amount of energy needed to create a neodymium magnet? What's the cost ratio? These magnets are expensive, but is the amount of energy needed to create them very high (2Kw)? Or is it still pretty reasonable? Does anyone have a link with accurate estimations?

So I am trying to come up with a magnet parts lifting device that can be temporarily turned off Their theory was, take two magnets (7x7x1.5mm in this case) place them between two iron plates with opposing poles and there should not be any field lines leaving the iron. Take away one of the...

Hello, I am trying to calculate the magnitude of the attractive force between a cylindrical magnet and a sheet of iron. A bit of searching found some equations that can be used to calculate the force between two magnets but I could not find anything related to magnetic force on non...

When I placed the south end of a magnet on the right hand side of the green CRO spot (when timebase is off) facing towards the left hand side of the screen, I expected the spot to move downwards in accordance with the left hand rule, but instead it moves upwards. The spot also moves down when I...

Homework Statement Attached file shows the problem statement. The Attempt at a Solution I can do this problem easily. Problem is that there's just one step in my book's derivation that I don't understand. It sets ρ equal to the hypotenuse in the triangle and then says that: dl = ρ/sinθ...

Homework Statement this is an experiment from lab.. i have pendulum - mass (iron) hanging from a massless cord. under the mass there is a magnet. the movement of the pendulum is in a small angle. i repeat the experiment 5 times - each time in a different distance between the iron mass and...

Hey guys, sorry if this is wrong place to post this. If it is let me and I will try and find the right place. It was the only category where I saw something about energy and physics. This is also probably a basic question but I hope you don't mind me asking. Let's say you have an electro...

I would like to build an electro magnet capable of causing piano strings to vibrate without the strings being struck first. As long as the hammers are up, the strings would vibrate on their own accord. An E-bow, used by guitarist for the same purpose, will (sort of) work on a limited range on...

If I have a cylindrical permanent magnet and an electromagnet with both poles facing each other, would the permanent magnet attract to the soft-iron core of the electromagnet? Assuming both magnets are restricted on an axis and have +/- equal strength (~375lb pull force, 2" cross sectional...

Hi All, I was wondering: for a given size and strength magnet sticking to a wall of a given material and surface area, does the thickness of the wall affect the strength of the attraction? What are the governing equations at play? I am trying to gain insight as to why or why not the...

Why is it that a radio wave or a microwave is not affected by a magnetic field from a electromagnet or bar magnet? I know they are self contained and so no outside force should effect them but that I can't get my head around. The idea I have is that since the Electromagnetic field is...

Hello everyone, I have a quick concept question for electrodynamics course. If a cylindrical magnet, axially magnetized, is rotated round its own central axis, axis of symmetry, will this create a rotating magnetic field in the vicinity of the magnet? what if the magnet was rotated around in...

This may be a dumb question but I am so lost and would appreciate any help! Is there a way to quantify the attractive force between a metallic object and a magnet? With numbers not qualitatively? I was under the impression that with a metallic object everything was microscopic so itd be...