Does a Decreasing Magnetic Field Induce Conventional Current?

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Homework Help Overview

The discussion revolves around the concept of electromagnetic induction, specifically focusing on whether a decreasing magnetic field induces a conventional current in a circuit. The context involves a square loop experiencing a changing magnetic field and the implications of this change on current flow, particularly in relation to an external voltage supply.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the relationship between induced emf and conventional current, questioning how these interact with an external voltage source. There are attempts to clarify the nature of the induced current and its classification as conventional current.

Discussion Status

The discussion is active, with participants providing insights into the principles of electromagnetic induction and questioning the implications of energy stored in magnetic fields. Some participants express confusion or seek further clarification on the concepts being discussed.

Contextual Notes

There are references to specific circuit configurations and the role of impedance, indicating that assumptions about the circuit's characteristics may be under examination. The discussion also hints at the need for a deeper understanding of transformer operation in relation to the topic.

learning_phys
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[tex]\xi = - \frac{dB}{dt}[/tex]

Is the emf induced by a changing flux. Is the current created by this emf conventional current?

For example. Say there is a square loop in the plane of this page, with a decreasing magnetic field going INTO this page. This creates a clockwise current to battle the change in B. Now say there was a voltage supply attached to this loop so it looks like this:

|----------|
| x x x x x |
| x x x x x |
|---l |-----|
-V+

The voltage V gives a conventional current to go clockwise. Would the current introduced by scenario above add do this voltage or subtract?

I guess my question is, is the clockwise current induced by the decreasing magnetic field a conventional current?
 
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think about it this way, there is energy stored in the magnetic field and that energy has to go somewhere.
 


and that does not help at all, gran(d)pa
 


how do you suppose that transformers work?
 


learning_phys said:
[tex]\xi = - \frac{dB}{dt}[/tex]
Is the emf induced by a changing flux.
Yes.
Is the current created by this emf conventional current?
Actually it's voltage by Faraday's Law of Induction. If there is an impedance for it to operate on then current flows.
For example. Say there is a square loop in the plane of this page, with a decreasing magnetic field going INTO this page. This creates a clockwise current to battle the change in B. Now say there was a voltage supply attached to this loop so it looks like this:

|----------|
| x x x x x |
| x x x x x |
|---l |-----|
-V+

The voltage V gives a conventional current to go clockwise. Would the current introduced by scenario above add do this voltage or subtract?
By the right hand rule the current would be clockwise as well.
I guess my question is, is the clockwise current induced by the decreasing magnetic field a conventional current?
Yes. It's a conductor. Presumably it has impedence somewhere in the circuit.
 

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