Is back EMF equal to the induced EMF in self-induction?

AI Thread Summary
In self-induction, an induced EMF generates a back current that opposes changes in current intensity, but it does not necessarily become zero until the intensity stabilizes. The discussion highlights the distinction between instantaneous current and the rate of change of current, which affects magnetic flux. There is contention over the claim that the back EMF is "equal in magnitude" to the induced EMF, with participants arguing that this is not correct. The consensus suggests that the back EMF does not have to be equal to the induced EMF in all scenarios. Understanding these nuances is crucial for grasping the principles of self-induction.
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In the case of self induction, when the intensity increases gradually an emf is induced which generates a back current " equal in magnitude, opposite in direction " to oppose the increase, so if that is right shouldn't the intensity in the coil Become ZERO till the intensity becomes steady?
 
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Well, there are two things going on here. There is the instantaneous current and then there is the rate of change of current. You have to think again at which one provides the magnetic flux and which one provides the change in flux.
 
ElmorshedyDr said:
an emf is induced which generates a back current " equal in magnitude, opposite in direction " to oppose the increase,
Where did you get the bolded part (equal in magnitude)? It is not correct.
 
Last edited:
DaleSpam said:
Where did you get the bolded part (equal in magnitude)? It is not correct.
So it doesn't have to be equal ?
 
I cannot think of any example where it is equal.
 
Thread 'Inducing EMF Through a Coil: Understanding Flux'

Thread 'Inducing EMF Through a Coil: Understanding Flux'

Thank you for reading my post. I can understand why a change in magnetic flux through a conducting surface would induce an emf, but how does this work when inducing an emf through a coil? How does the flux through the empty space between the wires have an effect on the electrons in the wire itself? In the image below is a coil with a magnetic field going through the space between the wires but not necessarily through the wires themselves. Thank you.
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Thread 'Griffith, Electrodynamics, 4th Edition, Example 4.8. (Second part)'

Thread 'Griffith, Electrodynamics, 4th Edition, Example 4.8. (Second part)'

I am reading the Griffith, Electrodynamics book, 4th edition, Example 4.8. I want to understand some issues more correctly. It's a little bit difficult to understand now. > Example 4.8. Suppose the entire region below the plane ##z=0## in Fig. 4.28 is filled with uniform linear dielectric material of susceptibility ##\chi_e##. Calculate the force on a point charge ##q## situated a distance ##d## above the origin. In the page 196, in the first paragraph, the author argues as follows ...
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