Magnets and Electric Current

Alternating current will only tend to demagnetize the magnet, whereas direct current will tend to increase or decrease the magnetic field strength, depending upon which direction the current flows. Keep in mind that magnetic fields and electric fields are orthogonal to each other, and electric current is not normally used to initially magnetize a material, since many (such as ceramic magnets) are not very electrically conductive.

Ok thank you for the reply

So lets say i have 2 neo magnets in a horzontal slide (i.e one magnet is fixed at one end of the slide with the north pole in the direction towards the centre of the fixture, and the othe magnet on a slide with the north pole pointing towards the other magnet) These 2 magnets will repel each other but one one can slide. if i placed the sliding magnet so it is just outside interation with the fixed magnet. I then apply a 12v 30A dc electrical current to the fixed magnet,

Will it increase the repelling force in that magnet? and push the other magnet away?

Gareth

I would think an aspiring physics student could devise a way to test this theory.

You certainly don't want us to do your homework for you, so you've said.

If you announce that you are a student, people will be more willing to help, without actually doing your work for you.

Good luck.

Yes I am a student.

At the moment I am learning about SI symbols, how much energy it takes to boil water and rearranging equations. I am a design engineer by trade, The magnet with electrical current is not anything to do with my homework, It is just a theory on using magnets to convert linear motion into rotary motion.

So I am asking for basic knowledge of magnets and electrical currents as this is something I have never looked at before.

Gareth

Your #4 must've come in while I was composing my #5 - sorry if it came over as a bit condescending.

My first thought was "if there is any change, it's going to be pretty tiny"*, so I started looking at the experimental set-up.

*Why tiny? How often have you seen wires jump about when current starts flowing through them?**

**Now you'll probably say "But we did this at school - two parallel wires freely suspended*** - when current was applied, they moved apart or towards each other, depending whether the current was in the same or the opposite direction" - also remember that they never showed the same experiment with the wires end-on to each other.

***This may be a hint****

****D'oh! I'm doing it again.

"if i placed the sliding magnet so it is just outside interaction with the fixed magnet ..." then you'd have to place it a very very long way away. How far do you think you have to go before two magnets stop interacting with each other?

I can visualize the experiment you're trying to set up - but it's got a few shortcomings. You said the slide is horizontal, so (ignoring all other magnetic fields) we have attraction or repulsion between the two magnets, and friction as the only forces in action. Earth's gravity is normal to the slide, so has no effect other than to pull the magnets against the slide (so that friction comes into play). Let's assume that the gravitational force between the magnets is small enought to be ignored, and they are equally charged so there is no electrostatic force.

The thing that's going to f*ck up your experiment is the friction. If you tried your experiment and couldn't see any difference, would you say that the electric current has no effect - or would you perhaps think that the effect is too small to detect, given all that nasty friction? Can you think of another experimental set-up that will eliminate the friction as a variable, and let you measure much smaller differences in the force between the two magnets?

I agree, as long as this is conceptual, we can change things around without any problem.

After all the question is:"Does it make the magnetic switch poles? or make the magnet have more magnetic force?"

Lyn

Hi guys,

Some good ideas here, Ok lets change this a bitlets say the sliding magnet is on roller bearings and what if i put a weighing scale behind the sliding magnet (a digital one). So that i could zero the scale when i have put the sliding magnet into a bit of interation with the fixed magnet.

Gareth

As described, passing a current through the magnet in any direction will weaken the field. To modify the field within the magnet, you would need to make a coil around the magnet and apply DC current. The field will either increase or decrease depending on the direction of the current (left hand thumb rule).

There are some quries to be clarified:

1. Where the hole & in which plane?

2. If you look the magnetic field around a conductor it is a cicular around the cunductor.

3. It will poduce :

Don't care formula, just see the direction of lines of force.

And consider the the outlines as plane of magnet

a. >>>>>>>>>> is the direction of lines of force internally.

b. by the right-hand rule drection of lines around the conductor,

AND INSIDE of magnet will be CCW.

c. Due to Current [DC] magnetic-lines will aid field [strengthen] on lower side

& oppose [weaken]on the upper side.

The field inside will be modified which depends on the strength of current.