How Fast Must the Magnetic Field Change to Induce a 3.4 A Current in a Coil?

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SUMMARY

The discussion focuses on calculating the rate of change of the magnetic field (B) required to induce a 3.4 A current in a 102-turn coil with a diameter of 3.8 cm, using copper wire with a diameter of 0.59 mm. Participants clarify the use of formulas such as R = ρL/A for resistance and B = μ₀NI/2r for magnetic field calculations. Key issues include determining the correct length (L) of the wire and the area (A) for resistance calculations. The final consensus suggests that the diameter of the coil, not the wire, should be used to find L, leading to a corrected calculation of B.

PREREQUISITES
  • Understanding of electromagnetic induction principles
  • Familiarity with Ohm's Law and resistance calculations
  • Knowledge of formulas for magnetic fields and coils
  • Basic proficiency in geometry for calculating areas and circumferences
NEXT STEPS
  • Study the principles of electromagnetic induction in detail
  • Learn about the application of Ohm's Law in circuit analysis
  • Explore the derivation and application of the formula B = μ₀NI/2r
  • Investigate the significance of wire diameter and coil dimensions in electrical calculations
USEFUL FOR

Students in physics or electrical engineering, educators teaching electromagnetic theory, and anyone involved in practical applications of electromagnetism and circuit design.

  • #31
Acoil = 7.4506 e^-4
I don't get this. I think you may have made a calculator error. The diameter is 0.038 m, right?
So L = pi*Dwire*102 = 0.18906m
This should be Dcoil instead of Dwire. Dwire tells you nothing of how long the wire is. The diameter of the coil tells you that.

If you fix these two things I think the rest should be OK.
 
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  • #32
okay so I got an answer or 35.243 T/s and it's still wrong :(
 
  • #33
actually I forgot to change the L value when I calculated the Resistance so now I am getting 2269.9 T/s which seems extremely large! Is that what you got?
 

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