Attraction between a charge and a magnet

In summary, the compass needle is attracted to the charge on the metal sphere no matter which pole is closer. This happens because the electric field created by the electrons in the compass is stronger than the magnetic field.
  • #1
DRC12
41
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In physics lab we positively charged a metal sphere then placed a compass near it and both ends of the compass were attracted to the sphere. I know magnetic fields are created by electrons, so I made the assumption the compass is attracted to the positive charge because the electrons in the compass are attracted to the positive charge thus the interaction is purely electric. I'm not sure if magnets are negatively charged thou. Is this the basic idea? Or does it have to do with the interactions between magnets and electric charges?
 
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  • #2
Was the metal sphere made of steel or iron?
 
  • #3
You should have repeated the experiment with an unmagentized needle ;)
How would you determine if the compass needle carried a net charge?

Anyway - assuming you cannot do more experiments before you need to hand in your report for this one, you can assume the compass needle had a neutral charge (but you should state that assumption in the report). It is also a metal - a conductor.

Before you start thinking in terms of charges on the compass needle - what determined which pole was attracted to the charge? Something about the way you positioned the compass? Since neither pole was favored - what does that tell you about the magnetic field about the charged object?

Now back to considering charges...
What happens when a neutral conductor is brought close to a charged object?
(You've probably seen the effect in an electroscope - but what causes it?)
 
  • #4
First, so no-one gets angry at more for posting homework in the non-homework section, this isn't for a report I'm just trying to figure out what was going on. The magnetic field on the charged object is unaffected by which end of the compass is closest to it. Because the compass is a conductor, when it's brought near the charge the electrons gather towards the positive charge creating a force on the needle to go towards the charge. So this means it doesn't matter whether the charge was positive or negative, because if it was negative the electrons in the compass would have moved as far from the charge as possible i.e 180 degrees from the charge.
 
  • #5
Another small question, does a magnetic field have an effect on a charged object that is not magnetic? and vice-versa
 
  • #6
DRC12 said:
Another small question, does a magnetic field have an effect on a charged object that is not magnetic? and vice-versa
Perceptive question - a changing magnetic field will affect the charges in a conductor. When you bring the compass needle close, you are changing the magnetic field at the charged sphere.

This is why I asked you about what determined which pole was attracted and why (probably) @technicion asked if the metal sphere was iron or steel.
 
  • #7
Yes...it would be interesting to know what the charged sphere was made of.
If it was iron or steel then the compass needle would be attracted even if the sphere was not charged
 
  • #8
Simon Bridge said:
Perceptive question - a changing magnetic field will affect the charges in a conductor. When you bring the compass needle close, you are changing the magnetic field at the charged sphere.
But if the compass is still then the magnetic field isn't changing is it? The compass was brought towards the charged object and then held there.

technician said:
If it was iron or steel then the compass needle would be attracted even if the sphere was not charged
Because the magnet would induce a magnetic field in these metals? and all the lab manual says is that the sphere was conducting
 
  • #9
DRC12 said:
But if the compass is still then the magnetic field isn't changing is it? The compass was brought towards the charged object and then held there.
That's right - but the effect of the motion can still result in a deflection of the needle.
If the compass was oriented so the north pole was initially closer to the charged sphere but the south pole ended up attracted to the sphere, then there could have been an induction effect.
Because the magnet would induce a magnetic field in these metals? and all the lab manual says is that the sphere was conducting
... so if this was a long-answer in an exam, you'd do well to mention the possibility that the conducting sphere has some iron in it.

You should be able to see that quite a lot of things could have been happening.
 
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  • #10
Well thanks a lot there's clear's things up
 
  • #11
That's the fun part of asking scientists about something - you end up with more answer than you bargained for :)
 

Related to Attraction between a charge and a magnet

What is the attraction between a charge and a magnet?

The attraction between a charge and a magnet is a fundamental force of nature that occurs when two objects with opposite electrical charges or magnetic poles are pulled towards each other. This force is known as electrostatic attraction or magnetic attraction, depending on the types of objects involved.

How does the attraction between a charge and a magnet work?

The attraction between a charge and a magnet is caused by the interaction of electric and magnetic fields. When a charged particle or object is placed near a magnet, the magnetic field of the magnet exerts a force on the charge, causing it to move towards the magnet. Similarly, when a magnet is placed near a charged object, the electric field of the charge exerts a force on the magnet, causing it to move towards the charge.

What types of charges and magnets can attract each other?

Any type of charge (positive, negative, or neutral) and any type of magnet (permanent or electromagnet) can attract each other, as long as they have opposite polarities. For example, a positively charged object will be attracted to a negatively charged magnet, and a north pole of a magnet will be attracted to a south pole of another magnet.

Can the attraction between a charge and a magnet be explained by any other theories?

The attraction between a charge and a magnet can be explained by the theory of electromagnetism, which is a fundamental force of nature that describes the relationship between electric and magnetic fields. This theory, along with quantum mechanics, provides a comprehensive explanation of how the attraction between a charge and a magnet works.

What are some real-life applications of the attraction between a charge and a magnet?

The attraction between a charge and a magnet has numerous real-life applications, including electric motors, generators, speakers, and MRI machines. It is also used in everyday objects such as refrigerator magnets, magnetic toys, and compasses. The attraction between a charge and a magnet is also essential in the production and distribution of electricity.

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