Question related to electromagnetic theory

AI Thread Summary
When the switch in a circuit with an iron-cored inductor and a DC source is opened, the interruption of current flow leads to a rapid change in the magnetic field. This change induces a back electromotive force (emf) due to self-induction, which can generate a high voltage across the switch contacts. The resulting voltage can exceed the breakdown voltage of air, causing a spark or electrical arc to jump across the contacts. Understanding this phenomenon involves applying Faraday's law of electromagnetic induction and the concept of inductance. The discussion emphasizes the relationship between current interruption, magnetic fields, and induced voltages in explaining the spark.
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Question:
A circuit contains an iron cored inductor, a switch and a DC source arranged in series. The switch is closed and after an interval reopened. Explain why a spark jumps across the switch contacts.
Attempt:
I guess it's related to self induction and back emf but am unable to understand how a spark can be produced in such a case...
 
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on the right track, to produce an electrical arc, you first need quite a large voltage...

thinking about what's going on, before opening the switch you have a steady flow of current through the inductor, which produces a magnetic field

when you open the switch you immediately intererupt the current & so the magnetic field...

can you find any equations to help explain what is going on...
 
Thread 'Have I solved this structural engineering equation correctly?'

Thread 'Have I solved this structural engineering equation correctly?'

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