- #1
quantumfoam
- 133
- 4
Does any moving charge generate a magnetic moment? I thought so because a moving charge generates a magnetic field.
quantumfoam said:I think since a magnetic field should have a magnetic moment, which you can use to calculate the magnetic field, a moving charge no matter what kind of motion, generating a magnetic field, should have a magnetic moment.
quantumfoam said:But if I wanted to, would I be able to describe the magnetic field of a moving charge in terms of its magnetic moment?
Why do you say that finding moment of inertia about an arbitrary point is ridiculous? It's perfectly valid and there are well-defined moment of inertia's about any axis at any point in a system!TopiRinkinen said:An analogy in mechanics would be calculating the moment of inertia of a disc at point which is NOT the center of mass. Which seems ridiculous.
quantumfoam said:The magnetic moment points from the south pole to the north pole of a magnet, which I believe to imply magnetic dipoles. If a moving point charge generates a magnetic field according to the Biot-Savart law, (which shows the two magnetic poles of the moving point charge) shouldn't the moving charge also generate a magnetic moment regardless of what type of motion it is executing? Please correct me if I am wrong.
quantumfoam said:This would give our moving charge a kind of "donut" shape of some sort. We can't define which one is south or north, but we can sure see the poles
I still don't understand this... the field is in the shape of a cylinder with the wire as it's axis.quantumfoam said:hence the "donut" shape of the magnetic field
Even if I take it to be a donut, where do you find endpoints in a 'donut'?quantumfoam said:Since it has two endpoints, (which, by the way, I'm assuming implies magnetic dipoles)...
That's what I pointed out earlier... If the direction of the field keep on changing with position, how can there a fixed north pole for the magnetic moment to point at!quantumfoam said:... it is a constant vector pointing from the south pole to the north pole of the magnetic field.
Oh! Now I get what you want to say... Well then, if that is the case, then surely the magnetic field has a constant direction and hence a fixed north and south. Now we can safely ask whether there's a moment or not. But there's still one problem... the distance between the two poles! How do you get that?quantumfoam said:Nooooo! I don't think we are on the same page here is all. (: I don't think imagining our charge to be a wire is going to help because a wire and a point charge have different magnetic field shapes. What I meant by the donut shape of our point charge is that it is not completely in the shape of a donut, but it has some characteristics. In a real donut, there is a hole, which I totally understand why you got confused (that was my mistake by not being clear enough), but in the magnetic field of our point charge there is no hole. It has the same curving features of a donut but it doesn't have a whole. It has the same magnetic field shape as a solenoid. Our moving point charge is moving at a constant velocity and through a vacuum (classical vacuum). If it is not accelerating or near any force, how will the direction between north and south change?
quantumfoam said:A point charge moving at a constant velocity will have the same magnetic field shape as a bar magnet.
oops! sorry i wrongly wrote "magnetic field"!chill_factor said:yes moving charges produce a magnetic field.
you can explicitly see this when you have a static charged particle in one frame moving relative to another frame. in relativity, neither electric fields nor magnetic fields are invariant in different frames, but the electromagnetic tensor is. You take the Lorentz transformation of the electromagnetic tensor that describes a static charged particle in the rest frame in order to transform it into the moving frame and write out the terms explicitly.
You will find that the B'[itex]_{i}[/itex] terms in the moving frame will have nonzero components related to the E field in the rest frame.
Moving charges create magnetic moments, which are the result of the magnetic field produced by the movement of the charges. The strength and direction of the magnetic moment is directly proportional to the speed and quantity of the moving charges.
Moving charges and magnetic moments play a crucial role in many modern technologies, such as electric motors, generators, and MRI machines. They are also used in household appliances like refrigerators and speakers.
Yes, magnetic moments can be manipulated through the use of external magnetic fields. This allows for the control of electronic devices and the production of magnetic materials.
A magnetic moment is a property of a particle or object, while a magnetic field is the region around a magnet or moving charge where its influence can be detected. In other words, a magnetic moment creates a magnetic field, but a magnetic field does not necessarily create a magnetic moment.
The direction of the magnetic moment is perpendicular to the direction of the moving charges. This means that if the charges are moving in a straight line, the magnetic moment will be oriented at a 90-degree angle to the direction of the movement.