# Magnets In Transformers; Crazy Question Help Please

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#1
Guys Why Does A Change In Magnetic Field Induce a Potential Difference Which Makes Current Flow?
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5 years ago
#2
(Original post by )
Guys Why Does A Change In Magnetic Field Induce a Potential Difference Which Makes Current Flow?
Not everybody is braced to provide you with an intuitive explanation, and so neither am I. What the can do is to talk from equations.
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#3
Not everybody is braced to provide you with an intuitive explanation, and so neither am I. What the can do is to talk from equations.
talk from equations
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5 years ago
#4
(Original post by )
talk from equations
Have you studied Faraday's law of induction? It states that an e.m.f is induced in a conductor when the magnetic field surrounding it changes and the magnitude of the induced e.m.f is proportional to the rate of change of the field.

E(induced e.m.f)= -N delta magnetic flux/delta time

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#5
Have you studied Faraday's law of induction? It states that an e.m.f is induced in a conductor when the magnetic field surrounding it changes and the magnitude of the induced e.m.f is proportional to the rate of change of the field.

E(induced e.m.f)= -N delta magnetic flux/delta time

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Okay, no i haven't i am only currently studying A2, however i'm doing the BMAT and it mentions a magnetic field inducing a potential difference. All i'm wondering is how a magnetic field can cause work done for charge. if you get what i mean.

like V=w/Q so how can a magnetic field cause that.
0
5 years ago
#6
(Original post by )
Okay, no i haven't i am only currently studying A2, however i'm doing the BMAT and it mentions a magnetic field inducing a potential difference. All i'm wondering is how a magnetic field can cause work done for charge. if you get what i mean.

like V=w/Q so how can a magnetic field cause that.
Well, to be honest I'm not very confident to "suggest" an explanation to that, though I do believe you are asking a reasonable question. I'm sure many people can see your question so hopefully someone will come along and help you with it.

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0
5 years ago
#7
(Original post by )
Okay, no i haven't i am only currently studying A2, however i'm doing the BMAT and it mentions a magnetic field inducing a potential difference. All i'm wondering is how a magnetic field can cause work done for charge. if you get what i mean.

like V=w/Q so how can a magnetic field cause that.
When magnetic flux linkage is changing, an emf is induced. An example of the flux linkage changing is a wire loop being rotated in a magnetic field. The rotation is where the energy is coming from for the 'work done'. I think that's correct anyway.
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#8
Well, to be honest I'm not very confident to "suggest" an explanation to that, though I do believe you are asking a reasonable question. I'm sure many people can see your question so hopefully someone will come along and help you with it.

Posted from TSR Mobile
1
#9
(Original post by Alex621)
When magnetic flux linkage is changing, an emf is induced. An example of the flux linkage changing is a wire loop being rotated in a magnetic field. The rotation is where the energy is coming from for the 'work done'. I think that's correct anyway.
Okay then, i get what you mean by the work done coming from moving it but what does the magnetic field have to do with it?
Why can you just rotate it and the work done from that will supply a potential difference if you know what i mean?
0
5 years ago
#10
(Original post by )
Okay then, i get what you mean by the work done coming from moving it but what does the magnetic field have to do with it?
Why can you just rotate it and the work done from that will supply a potential difference if you know what i mean?
Oh ok, sorry I can't help you, I've never really thought about it and I can't find a clear explanation on the internet.

If I were to guess, I would say that it involves Lenz's law... So when you are moving a wire inside a magnetic field, a current is induced to try to counteract the change in magnetic flux linkage. When a current flows through a wire, a magnetic field is generated around the wire so maybe it has something to do with this and the only way for the wire to oppose the changes which are happening is to generate it's own magnetic field and the only way to do that is by allowing a current to flow?
1
5 years ago
#11
(Original post by )
Okay then, i get what you mean by the work done coming from moving it but what does the magnetic field have to do with it?
Why can you just rotate it and the work done from that will supply a potential difference if you know what i mean?
For that part I can say that magnetic field and a rotating wire are interdependent for producing a potential difference. If you just rotate a wire without the presence of a magnetic field then you will just rotate it as a result of the work you have done. A magnetic field is needed so that the field can exert a force on the charged particles, electrons, within the wire. Thinking about it again, I think the change in magnetic field is to indicate the relative motion between the magnetic field and charged particles.
1
#12
For that part I can say that magnetic field and a rotating wire are interdependent for producing a potential difference. If you just rotate a wire without the presence of a magnetic field then you will just rotate it as a result of the work you have done. A magnetic field is needed so that the field can exert a force on the charged particles, electrons, within the wire. Thinking about it again, I think the change in magnetic field is to indicate the relative motion between the magnetic field and charged particles.
Thanks, that's what i wanted to find out.
It all comes down to me wanting to know how a magnetic field can affect charge. I understand how an Electric field can but just not magnetic, i might just hope that it comes up in the A2 AQA syllabus for physics.
0
5 years ago
#13
(Original post by )
Thanks, that's what i wanted to find out.
It all comes down to me wanting to know how a magnetic field can affect charge. I understand how an Electric field can but just not magnetic, i might just hope that it comes up in the A2 AQA syllabus for physics.
Yeah, there is a chapter on magnetic fields in A2 but there is not much detains about it.
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