Permanent magnet Definition and 109 Threads

Hi, I have two questions about permanent magnets: 1. How do you calculate the work done by a permanent magnet on, say, an iron plate? 2. I am aware that the force exerted on an object by a magnet depends on the surface area. Is it also affected by the thickness of the object to a...

hey how would I go about calculating the B field of a bar magnet? I've already managed to calculate the electric field between two charged particles etc and draw that, but I just can't see where to start with this one as its not just a point at north and south but a whole load of atoms...

Hi: I'm having real trouble finding resources for the problem of accurately calculating (and drawing the field lines for) a magnetic field around a permanent bar magnet, or between two permanent magnets (I assume this is the same problem, as fields are superposable). I've found lots of sites...

what is the average size of a domain? and how are "permanent" magnets made? thanks, erin.

Evryone knows that the work done by a magnetic field is zero. Then how does a permanent magnet lift iron filings.

Let’s say I make ball (sphere) out of permanent magnet material. Where will be N/S poles, will they take fixed position or, as I think, position won't be fixed. p.s. same for magnet ring [/color]

Hi, I have a submerged magnetic water pump that is pushing too much water at 8500L/hr. I know that the propeller rpm depends on the frequency of the AC supply but how can I build a simple circuit to reduce the frequency? Thanks :smile:

If I have an internal resistance of the motor and the value of flux and the generator constant, can I simulate the system's performance by a circuit with two circuits in series, one being the internal resistance, and the other being the load, and the voltage source being the armature voltage?

What is the most efficient way to build a permanent magnet linear generator--AC or DC, it makes no difference. I'm working on a personal project but don't know where to start. I'm assuming that a generator similar to the one inside of a ForeverFlashlight is probably the best way to go, but I'm...