Magnet Definition and 912 Threads

A moving magnetic field will produce current in a wire. The Earth's magnet field goes beyond the moon. Does that mean bases on the moon could somehow get free energy from a coil setup as it's effectively perpetually moving through Earth's magnetic field?

Homework Statement A bar magnet is held above the center of a wire loop lying in the horizontal plane, as shown in the figure below. The south end of the magnet is toward the loop. After the magnet is dropped, what is true of the current in the resistor as viewed from above? (Select all that...

Homework Statement A magnet of mass 0.10 kg is dropped from rest and falls vertically through a 35.0 cm copper tube. Eddy currents are induced, causing the copper to warm up. The speed of the magnet as it emerges from the tube is 1.50 m/s. How much heat energy is dissipated to the environment...

hi who can help me to show field magnetic analysis of quasi halbach permanent magnet in ansoft maxwell? thanks

I am attempting to build a linear induction flashlight. I was wondering if the concept below could be used to make the magnet slide down a pole inside a coil with no friction. The interior of a tube magnet with an S polarity would slide down the S end of a rod magnet, that way the inside of the...

Doubtless you are all familiar with a rail gun made by using permanent magnets. An example is given here: http://sci-toys.com/scitoys/scitoys/magnets/gauss.html Assuming the railgun could me made curved, won't it be possible to build a curved track to transport the projectile - assume...

Hello. I'm looking to build a strong electro magnet with ac power. I was going to use a MOT transformer so the primary was going to be the same windings. For the secondary windings though I'm trying to decide if I want to go with a higher current or voltage. I would assume that a stronger...

I have an aluminum tube with 1.25" ID and 2.25" OD. I drop a neodymium grade N50 magnet, 1" dia, 2" long into the tube and enjoy watching the magnet drift very slowly down the tube. Lenz's law in demonstration. The paramagnetism of aluminum allows the magnet-in-motion to induce eddy currents...

Hello , firs of all I know that every magnet has two poles ad the field lines exit one pole and enter into the other , now if we take a bunch of magnets , for simplicity assume an infinitely long line of magnets each separated by a distance , all of the magnets facing N-S N-S N-S , now do the...

Watch this video: Permanent magnets moving relative to a stationary copper tube generate Eddy currents which result in Joule heating of the copper. Simple enough. Let's change the problem to a rotor with 4 (circumferential) permanent magnets rotating inside a stationary (aluminum or...

When watching some videos about neodymium magnets, I came upon a very interesting phenomenon. Namely, the maker of the video put a large magnet near an old CRT TV. At first, a big black spot appeared on the screen. This means that the electrons were repelled from from the magnet and didn't...

Hi, Can somebody give me the formula for pull force of ring magnet(permanent. not solenoid or electric) on a metal rod. Also is the formula for pull force by a solenoid given below correct. If not let me know the correct one for the below. Force = ((N x I)^2 x μ x A) / (2 x g^2) N =...

I'm planning to use some permanent magnets in a new kind of heat engine I designed. The properties I am seeking are: - Resistance to shockwaves and high acceleration, - Relatively great strength/weight ratio, - and relatively high curie temperature. After a quick research, I think the...

The question is slightly deceiving however still simple for those academics therefore, here I present my question: If I take a para-magnetic material and put it very close to a homogeneous magnetic field, the para magnetic material will start to accelerate towards the magnetic body thus it...

I am working on impedance measurements of close-wound electromagnetic coils. I am using an Agilent LCR meter to measure the impedance of these coils over a frequency range of 20Hz-2MHz. When I perform the measurements, I get impedance magnitude and phase angle in degrees. I would like to...

Hello, It is my understanding that a moving magnetic can induce an electrical current, and that conversely, and electrical current can move a magnet. I believe that this is the basis by which speakers work (changing electric field causes vibration of the magnet that generates the sound)...

Hi all I've been trying to use weights, springs and elastic bands to basically decrease the bonding of a piece of metal and magnet. Basically what I am trying to achieve is as the magnet attracts the metal i want the attraction to weighed down consistently, but I am failing to do this as the...

Hi everyone. I was doing an experiment on the effects of varying the distance between the solenoid and magnet, the voltage across the solenoid, and temperature of the iron core inside the solenoid on the magnetic field produced and the magnetic repulsion between the solenoid and magnet...

Please watch this video (link: http://www.youtube.com/watch?v=JN-A3RryOC8) for reference. As you can see, the magnet does not slow down (at least, not appreciably) when falling through the copper coiled around a PVC pipe, and I can't figure out why.

What is the effect of temperature on a Magnet. I am not talking about curie temp. Just a higher temperature than room temp, say 150C. Magnetism will probably decrease due to heat. But what is the long term effect, say after a few months. Will the Magnet be back to its full power when bought...

Hello everyone, i am seeking for an ultra strong cylinder neodymium N52 magnet or something stronger if it exists(i know N52 is the strongest ^^) with these dimensions : length : 2-3cm diameter : 0.7 mm I have searched and talked with many companies but either they require...

what is the formula for force between current carrying solenoid (both cylindrical and toroidal ) and a permanent magnet.

So I was building a Gaussian gun for physics filming it at 300fps. See video: http://youtu.be/hZcAk3uBp58 While skipping frame by frame, I realized that all the magnets started drifting backwards after being hit. Can someone explain in detail what is going on? Sorry if my physics is not...

I was just doing a read-through of my freshman griffith's electrodynamics textbook ( I found my comprehension of electrodynamics slipping again ... always gets me edgy ) and I find my self flummoxed yet again. So he goes through an example of magnetic forces lifting a weight, and shows how it's...

Iron fillings form a particular arrangement when sprinkled around a magnet. The direction of magnetic field lines represented by the alignment of iron filings sprinkled on paper placed above a bar magnet. Image and description credits: Wikipedia If a magnet, which can...

Hi I have a question about a Synchronous Permanent Magnet Alternator (Small Wind Turbine Alternator) I want to understand the ratio between RPM and the Voltage from the Alternator. I can't find any equation for that ratio , and I read somewhere on the web , that if I have a load ,than the...

Sir what would be the life of permanent magnet motor which runs by the repulsion of north pols. Is magnets energy wasted during this repulsion process or not. Because it continuously work on repulsion of two north pols.

I am trying to make a very strong magnet that will only last for a short pulse, just a fraction of a second, with a high peak current. I am going to use 1mm (18awg) wire, so the resistance should be pretty low, but with even just 25m, it would be expected to have 0.5Ω. I would like to have...

Homework Statement A bar magnet, with pole strength 0.1 Wb and magnetic length (i.e. distance between the poles) of 5 cm, is placed so that one pole is 2 cm and the other 6 cm from a long, straight wire carrying a current of 6 Amps. The magnet lies in a plane perpendicular to the wire. Find...

I am working on a home made electromechanical actuator to replace the vacuum actuator on the front axle of my Jeep Cherokee. The vacuum actuator isn't the greatest and I have replaced it and the system lines few times. SO I figure, I know what force the vacuum actuator is putting out, I...

Hi, please could someone explain why the magnetic field is stronger at the poles of a magnet. I know that the field line density is strongest at the poles and more spaced out in the middle. I get that. I just wanted to know why the magnetic field is stronger at the poles than the middle of a...

Hey, everyone. I'm in my final year of my bachelors at uni and we have a class that's basically to teach us how to set up a research project (among other things). We've already done the lit review, a risk assessment, all of that jazz. The final assessment is to basically produce an...

Hi Guys Could someone please point out where I'm going wrong with the following problem. If I place a magnet on a vertical surface such that the magnet must resit the force of gravity in order to hold itself in place, will this magnet stay in place forever? If it does why does this not...

Homework Statement In which of the following will a current NOT be induced in the conducting loop? a. Magnet moving toward upright conducting loop of wire b. Magnet moving away from an upright conducting loop of wire c. Magnet moving toward a horizontal conducting loop of wire d...

Can it do such a thing or are the particles too small ? If it is possible can I take the electron gun out my cry is you AA batteries?

Hi! In the description of the Stern-Gerlach experiment made in Sakurai's book the magnet is shaped to have a pointed edge. What is that for?

Hey guys, It has been a while since I've done anything to do with magnetism and was wondering if I covered one side of a disc magnet is a non magnetic glue, would this weaken the polarity of this side? And the more layers of glue I 'paint' on, the weaker this side of the magnet is. In the...

Hi All! This is my first question/post here, so I will try to make it work! Homework Statement Ok, so the question is simple-ish. Homework Equations Faradays Law (ε=-NΔΘ/ΔT) The Attempt at a Solution Now, I understand the concept that as the magnet is falling towards the coil, the coil...

hi guys! i was wondering if the solid magnet part of a brushed dc motor needs to be strong in order to make a strong motor? I'm designing a motor from scratch and wondering if i should use an existing ferrite magnet that is somewhat strong or should I design a electromagnet that is stronger...

1. It is desired to determine the magnetic field of a bar magnet. The bar magnet is pushed through a 10.0-cm diameter circular coil in 2.50 × 10-3 s and an emf of 0.750 V is obtained. Find the magnetic field of the bar magnet. ε = 0.750 V d=0.10 m t=2.50x10-3 s [b]2. Homework...

Can a magnetic field bend space-time?

Hello this is my first time to post. I have an electromagnet powered by a car battery charger set at 12 volts the problem is I can't get the electromagnet to repel the neodymium magnet. I have tried switching around the positive and negative leads of the power supply and switching the side of...

I understand the "north" is where to field is "coming out of" and south is where it returns, and i can see how two magnets would repel and attract. However when electrons or protons are brought near magnetic fields they are deflected. Why? What determines which direction a negativley charged...

If i move a magnet back and forth in free space, will it radiate? If it does not then why?

This is about a famous thought experiment, cited by Einstein at the beginning of his first 1905 paper on SR, and discussed in textbooks and on this forum. I've fleshed it out with a specific set up, shown in the thumbnail. Seen in the S frame, a wire aligned in the y direction moves at speed...

Hi, I would like to clear some doubts over the field of a rotating magnet. I understand that in a typical alternator or generator , brushed or brushless , the current in the wires is induced because the opposite poles of either a permanent or electromagnet pass by the coils and the magnetic...

There are the famous experiments, which show, how an Oxygen soap bubble gets attracted by a magnet due to it's paramagnetism. And how a Nitrogen bubble gets repelled by it (in air)But how does one calculate the attraction force of this pure Oxygen soap bubble in air due to a magnet. I'm Sorry...

Hey guys, I'm an engineering student and for my project i am planning to use a power generator based on magnet and coil like those hand power shake flashlights. I am using gauge 45 AWG copper wires (0.051816mm) and coiled to have 200 coils. The coil size will be 2.5cm. The magnet i am using...

Homework Statement My 10 year old granddaughter started her new school term last week and was presented with an electromagnet problem by her new science teacher. The class is allowed to use any non-physical method to solve this for their lesson next Wednesday. A direct link to my 'Dropbox'...

Well, permanent magnets are made of ferromagnetic material. These magnets lose permanent magnetization above the Curie temperature(on heating) and behave as paramagnetic materials. The reason is thermal energy. The magnetic moments lose their initial configuration and no longer remain aligned...