How Is Current Induced in a Multi-Turn Coil with Changing Magnetic Field?

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SUMMARY

The discussion centers on calculating the average current induced in a coil with 253 turns, a resistance of 28 Ohms, and a cross-sectional area of 0.36 m², as the magnetic field drops from 2.2T to 0.0T over 0.33 seconds. The induced electromotive force (EMF) is calculated using the formula EMF = (Change in B * Area) / time, resulting in an EMF of approximately 2.4V. The average current is then derived using Ohm's Law (V = IR), yielding an induced current of approximately 0.0857A. The discussion highlights the importance of considering the number of turns in the coil when calculating total flux linkage.

PREREQUISITES
  • Understanding of Faraday's Law of Electromagnetic Induction
  • Knowledge of Ohm's Law (V = IR)
  • Familiarity with the concept of magnetic flux
  • Basic proficiency in algebra for solving equations
NEXT STEPS
  • Study Faraday's Law in detail to understand induced EMF calculations
  • Learn about magnetic flux and its relationship with coil turns
  • Explore advanced applications of electromagnetism in engineering
  • Investigate the effects of resistance on induced current in circuits
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Students in physics or electrical engineering, educators teaching electromagnetic theory, and professionals working with inductive components in electrical circuits.

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Homework Statement



A coil with 253 turns of wire, a total resistance of 28 Ohms, and a cross-section area of 0.36m^2 is positioned in a plane perpendicular to the field of a powerful electromagnet.
What average current is induced in the coil during the 0.33s that the magnetic field drops from 2.2T to 0.0T? Answer in units of A.


Homework Equations



E = BA / t
V = IR

The Attempt at a Solution



EMF = Change in B * Area / time
= (2.2 * .36) / .33

I plug that into V = IR

V = IR
[(2.2 * .36) / .33] = I * 28 Ohms
I = [(2.2 * .36) / .33] / 28 = 0.0857142857A

However I get the wrong answer.
I think it has something to do with the 253 coils of wire but I'm not sure.
Any help is appreciated.
 
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Yes, the emf you calculate is induced in each coil of wire, so the total flux linkage at the start is BAN where N is the nuber of turns.
 

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