Brief question about induced electric fields

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SUMMARY

The discussion centers on the relationship between the induced electric field and the magnetic field in a solenoid with a ferromagnetic core. The magnetic field B is defined as &bar;B = μ_r μ_0 n I &hat;z, where μ_r is the relative permeability, μ_0 is the permeability of free space, n is the number of turns per unit length, and I is the current. When the current I varies, an electric field is induced, which has a curl in the opposite direction to H, confirming that the induced electric field circulates in a direction opposite to that of the current I within the solenoid.

PREREQUISITES
  • Understanding of electromagnetic theory, specifically Faraday's law of induction.
  • Familiarity with solenoids and their magnetic properties.
  • Knowledge of vector calculus, particularly curl operations.
  • Basic concepts of ferromagnetic materials and their magnetic permeability.
NEXT STEPS
  • Study Faraday's law of electromagnetic induction in detail.
  • Explore the properties of solenoids and their applications in electromagnetism.
  • Learn about the relationship between electric fields and magnetic fields in dynamic systems.
  • Investigate the effects of varying current on induced electric fields in different geometries.
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Students of physics, electrical engineers, and anyone interested in the principles of electromagnetism and the behavior of electric fields in solenoids.

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Homework Statement



We have a solenoid with current I and n turns per unit length and (neglecting hysteresis) a ferromagnetic core. Find B and H.
Show that when I is varied an electric field is induced and draw it on a diagram.

Homework Equations



[tex]\nabla \times E = - \frac{\partial \bar{B}}{\partial{t}}[/tex]

The Attempt at a Solution



Finding B and H is fine: they come to [tex]\bar{B} = \mu_r \mu_0 n I \hat{\underline{z}}[/tex]
so [tex]\frac{\partial \bar{B}}{\partial t} = \mu_r \mu_0 n \frac{\partial I}{\partial t} \hat{\underline{z}}[/tex].
This implies that when I changes positively an electric field is induced such that the curl of it is in the opposite direction to H.

What I wanted to ask was does this mean that you get an electric field inside the solenoid that sort of goes around in a circle but in the opposite direction to I? I couldn't find it on the internet anywhere so I thought I'd ask to be sure. I've done a (rubbish) diagram of what I mean at http://users.ox.ac.uk/~quee2327/photo.JPG . The magnetic field is meant to be coming out of the page.
 
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This implies that when I changes positively an electric field is induced such that the curl of it is in the opposite direction to H. What I wanted to ask was does this mean that you get an electric field inside the solenoid that sort of goes around in a circle but in the opposite direction to I?

Yes, it does.
 
Great, thanks! I just wasn't sure of my maths.
 

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