Difference in potential induced by a magnetostatic field? O_o

In summary, according to the conversation, there is a difference in electric potential between a point on the surface of a stationary magnet and a point on a conductor that is placed underneath a dielectric. The potential difference decreases when the magnet is moved away from the conductor.
  • #1
Vectronix
64
2
Hi,

Why is there a difference in electric potential from a point on the surface of a stationary magnet to a point on a conductor that is placed underneath a dielectric? I placed some stationary magnets on top of glass or a piece of paper and put some aluminum under it, and touch one end of a voltmeter to the magnet and the other end of the voltmeter to the aluminum, the most I got was like 0.5 volts. When I remove the paper the potential difference is zero. If I remove the magnet, the potential difference is zero. When I have the magnet there at rest on top of the paper, which is above the aluminum, the potential difference is nonzero. When I start moving the magnet and the paper away from each other, the potential difference starts dropping quickly.

I thought that only a magnetic flux that is changing could induce a difference in potential. Anyone got an idea what's going on here?
 
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  • #2
Welcome to PF!

Hi Vectronix! Welcome to PF! :smile:
Vectronix said:
Hi,

Why is there a difference in electric potential from a point on the surface of a stationary magnet to a point on a conductor that is placed underneath a dielectric? I placed some stationary magnets on top of glass or a piece of paper and put some aluminum under it, and touch one end of a voltmeter to the magnet and the other end of the voltmeter to the aluminum, the most I got was like 0.5 volts. When I remove the paper the potential difference is zero. If I remove the magnet, the potential difference is zero. When I have the magnet there at rest on top of the paper, which is above the aluminum, the potential difference is nonzero. When I start moving the magnet and the paper away from each other, the potential difference starts dropping quickly.

I thought that only a magnetic flux that is changing could induce a difference in potential. Anyone got an idea what's going on here?

That's interesting … does anyone else know the answer? :smile:

(btw, does the potential difference reverse if you turn the magnet over? and does it work with other metals?)
 
  • #3
Hi Vectronix-
This is a very good question, as is the suggestion by tiny-tim-
Are you talking about a dc potential, or a transient pulse (like discharging something). What is the input impedance of your voltmeter? If is something like 20 megohms. and the distributed capacitance is certainly less than a nanoFarad, then the transient would be less than RC = 0.02 seconds. You also told us that there is no dc circuit (loop), so there can be no current, or contact potential. So it is a puzzle.

By the way, do you happen to have an analog voltmeter with a D'Arsonval movement? See
http://www.engineersedge.com/instrumentation/electrical_meters_measurement/darsonval_movement.htm
Is it affected by stray magnetic fields?
Bob S
 
  • #4
Hey, muchachos. :)

I'm sorry, I have been busy for a while, and I wasn't able to get to this sooner. Yes, the potential difference reverses when I flip the magnet over. It is a DC potential, not a transient pulse. The voltage started off at a certain level then it decreased some and stabilized after a short while when I did this. Yes, it works with different metals. I tried aluminum and copper.

I was thinking that maybe the dielectric that I use (paper, glass, etc.) and probably every other dielectric and its electric fields influence the magnetostatic field of the magnets I use thus becoming a time-varying field (changing magnitude and/or direction). But I am not sure why, if that is true. Any thoughts on this explanation? Anything to add to it? I will answer the other questions soon.
 
  • #5
Vectronix said:
I'm sorry, I have been busy for a while, and I wasn't able to get to this sooner. Yes, the potential difference reverses when I flip the magnet over. It is a DC potential, not a transient pulse. The voltage started off at a certain level then it decreased some and stabilized after a short while when I did this. Yes, it works with different metals. I tried aluminum and copper.

I was thinking that maybe the dielectric that I use (paper, glass, etc.) and probably every other dielectric and its electric fields influence the magnetostatic field of the magnets I use thus becoming a time-varying field (changing magnitude and/or direction). But I am not sure why, if that is true. Any thoughts on this explanation? Anything to add to it? I will answer the other questions soon.
Hi Vectronix-
Did you know that analog meters with D'Arsonval movements have moving magnets inside? Keep your magnets far away from these meters.
Bob S
 

1. What is a magnetostatic field?

A magnetostatic field is a type of magnetic field that is created by stationary electric charges, or by the movement of electric charges that are constant in time. It is also known as a static magnetic field.

2. How does a magnetostatic field differ from an electromagnetic field?

A magnetostatic field differs from an electromagnetic field in that it does not vary with time. An electromagnetic field is created by the movement of electric charges that are not constant, while a magnetostatic field is created by stationary electric charges or constant electric charges.

3. What is the difference in potential induced by a magnetostatic field?

The difference in potential induced by a magnetostatic field refers to the change in electrical potential energy that occurs when a charged particle moves through the field. This change in potential energy is caused by the interaction between the magnetic field and the charged particle.

4. How is the difference in potential induced by a magnetostatic field measured?

The difference in potential induced by a magnetostatic field can be measured using a voltmeter. The voltmeter measures the change in voltage that occurs when a charged particle moves through the field, which can then be used to calculate the difference in potential.

5. What are some practical applications of understanding the difference in potential induced by a magnetostatic field?

Understanding the difference in potential induced by a magnetostatic field is important in many fields, such as electrical engineering, physics, and materials science. It is used in the design of electrical devices, such as motors and generators, and in the study of magnetic materials and their properties.

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