Magnet Myths and Misconceptions

[tinman]

Tinman if the magnetic field were null at the dipole center as the Figure 8 claim requires then there would be nothing opposing the earth's magnetic field and the compass needle would align to the earth's field perpendicular to the dipole that is on the east-west line.  Try the experiment.  You will find that the conventional view prevails.

Like i said-the compass needle is only being attracted to the strongest magnetic attraction force/fields. Of course if i move the PM far enough away,the needle will point to magnetic north,otherwise we'd have a compass that points to every ones magnets. Im guessing at this point you are not going to draw the three simple diagrams i asked of you,despit the fact that i have done endless experiments for you and others,not to mention the cash forked out. How much time would it take you to do this? If three is to much,then draw just one electromagnet and it's(what you call)field lines,and flow direction arrows.-->Is this to much to ask?.

[MarkE]

@MarkE

I would like you to take some time and draw up an electromagnet the shape of a rod magnet-say 3 inches long and 1/2 inch in diameter for the core material. This will of course have the conductive wire wrapped around it. You will need 3 pictures/diagrams of this very same electromagnet. I would then like you to show the magnetic field building up around that electromagnet in three stages from the instant a current is applied to the inductor-i want to see this magnetic field build around the inductor. I know this happens at or close to the speed of light,but lets devide that by 3.
So we will have in the first diagram the field just starting to emerge,then the second diagram will show it half way built to its full potential,and the third will show the full field and strength of that field. I will then show and explain why there is no magnetic field at the cenetr point of that inductor/electromagnet between the two pole's.

I have done many experiments for you and others,so i hope you can take the time to draw these 3 simple diagrams.

P.S-you may use your fictional lines of force,and flow arrows for this experiment.

Brad

Depending on what is used for the core, the timescale will have to be much, much longer to see anything worthwhile.  We cannot instantaneously change the current in any circuit.  We can apply voltages with very high dV/dt's and once the voltage builds to a large value then the di/dt can become big.  The current will then build as long as we allow until ultimately being limited by the combined coil and circuit resistance.  Depending on the core material, the net magnetic field will either track the current (air core, or approximately with high resistance core), or lag due to eddy currents.  Both situations are depicted below.  If you are concerned with transmission line effects, then a wound coil masks those.  If you want to see something interesting in ns time frames then modeling a microstrip trace over a ground plane will do the job.  If you are going to measure transmission line effects at ns and ps scales then you will need an expensive time domain reflectometer.

[MarkE]

Like i said-the compass needle is only being attracted to the strongest magnetic attraction force/fields.

No the compass needle is acted upon by the vector sum of all fields it is exposed to.  Any misalignment with the net field imposes a torque on the compass needle that in the steady state it will closely align.

Of course if i move the PM far enough away,the needle will point to magnetic north,otherwise we'd have a compass that points to every ones magnets.

Which is exactly why an experiment where we place the test magnet orthogonally to the earth's magnetic north-south line.

Im guessing at this point you are not going to draw the three simple diagrams i asked of you,despit the fact that i have done endless experiments for you and others,not to mention the cash forked out. How much time would it take you to do this? If three is to much,then draw just one electromagnet and it's(what you call)field lines,and flow direction arrows.-->Is this to much to ask?.

Done in the post above.

[tinman]

So the below pic is depicting the magnetic field as you know it?

[MarkE]

So the below pic is depicting the magnetic field as you know it?

As it is for a solenoid coil or bar or cylinder PM magnet magnetized through its legnth.