Faraday's Law with Acceleration

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Discussion Overview

The discussion revolves around the application of Faraday's Law in the context of a circuit moving through a magnetic field, particularly focusing on the effects of acceleration versus constant velocity on magnetic flux and induced electromotive force (EMF). Participants explore the implications of these conditions on the induced current and the mathematical framework involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that while moving at constant velocity, the change in magnetic flux is zero, but this changes with acceleration, suggesting an increasing area akin to a "magnetic lawnmower."
  • Another participant questions the specifics of the circuit, asking whether it is completed and if currents are flowing, emphasizing the role of moving charges in inducing electric fields.
  • A participant clarifies that the circuit is completed and discusses the induced EMF from Faraday's Law, asserting that the magnetic flux should remain constant under a constant magnetic field, leading to confusion about how acceleration affects this.
  • There is a reiteration that if the magnetic flux is constant, it implies a time-independent electric field, which raises questions about the relationship between magnetic flux and induced currents in the circuit.
  • One participant challenges the expression of magnetic flux as (B)(A), suggesting a need for a more nuanced understanding of the mathematical relationships involved.

Areas of Agreement / Disagreement

Participants express differing views on how acceleration affects magnetic flux and induced EMF, with no consensus reached on the implications of these conditions. Some participants assert that the flux remains constant under certain conditions, while others question this assumption and its mathematical representation.

Contextual Notes

Participants highlight the need for clarity regarding the definitions of terms and conditions under which the discussion is framed, particularly concerning the state of the circuit and the nature of the magnetic field.

KabooHahahein
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I decided to join this forum because we were baffled on the following fact made by a professor. We were hoping to get this cleared up here, since the prof said the math was complicated.

Let's assume any arbitrary circuit (forming an area) moving at velocity v through a perpendicular field B to the plane of the area of the circuit. Now, the change in magnetic flux is 0 in constant v. However, it was pointed out that it is not 0 in any acceleration.

Our prof pointed out that it can be imagined as an increasing area as a magnetic lawnmower increases in speed.

How are the mathematics applied to this sort of problem?

Thank you!
 
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This is not the section to ask help for homeworks or assignments but I'll give you a go for this time. Please use the dedicated section for these kinds of purposes from now on.

You need to be more specific ;

Is the circuit is completed ?
Are there any currents flowing in the circuit ?
If so what are the specs ?

It has nothing to do with the area of the pcb or the circuitary. Your professor probably asked for this ;

Even if there is no current flow in the circuit, due to electrons in the pcb traces and the wiring, when the whole system accelerates you will be accelerating the electrons with the system. A moving charge will induce an electric field and a time varying electric field will induce a magnetic field . Taking derivative of velocity will give you acceleration and taking curl of electric field will give you minus derivative of magnetic field. From now on it's convenient to express ;

F = q.v x B

q is the coulomb of your charge, v is velocity and B is magnetic flux density vector.

Although this might not be the case at all, depending on what you really mean.
 
The circuit is completed, and we're talking about the induced EMF (resulting in an induced current) from Faraday's Law from a change in flux. Initially, I would assume that there are no currents on the circuit.

Now our issue is that the flux is (B)(A), and that it is constant under an externally generated constant magnetic field. Shouldn't the change in flux be 0, no matter whether the circuit is at constant velocity or acceleration through this constant field?

I apologize for making this look like homework. This is not anything assigned, we were simply curious as how it's possible that under a changing velocity, the change in magnetic flux through the loop would not be zero.
 
KabooHahahein said:
The circuit is completed, and we're talking about the induced EMF (resulting in an induced current) from Faraday's Law from a change in flux. Initially, I would assume that there are no currents on the circuit.

Now our issue is that the flux is (B)(A), and that it is constant under an externally generated constant magnetic field. Shouldn't the change in flux be 0, no matter whether the circuit is at constant velocity or acceleration through this constant field?

I apologize for making this look like homework. This is not anything assigned, we were simply curious as how it's possible that under a changing velocity, the change in magnetic flux through the loop would not be zero.

If flux (B) is constant you have a time-independent electric field also implying there is DC operation going on in the circuit.

There is no such thing as (B)(A).

[itex]\int[/itex][itex]\int[/itex] (dB / dt) ds = [itex]\oint[/itex] ([itex]\nabla[/itex]x E) ds
 

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