Calculating Current in a Coil with Given Magnetic Field and Parameters

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Homework Help Overview

The discussion revolves around calculating the current in a coil based on the magnetic field at its center, given specific parameters such as the number of turns, radius, and magnetic field strength. The subject area involves electromagnetism, particularly the behavior of magnetic fields in coils of wire.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the relationship between the magnetic field and the current in a coil, questioning the relevance of the number of turns and the radius in the equations provided. There is discussion about the distinction between a solenoid and a circular coil, and how to incorporate the number of turns into the magnetic field equation.

Discussion Status

Participants are actively engaging with the problem, with some offering insights into how to approach the calculation. There is a recognition of the need to consider the effect of multiple turns on the magnetic field strength, and some participants express confidence in their reasoning, though no consensus has been reached on the final solution.

Contextual Notes

There is a noted ambiguity regarding the length of the coil and how it relates to the radius in the context of the magnetic field equations. Participants are also navigating the implications of the coil being described as a "50-turn coil" and its significance in the calculations.

endeavor
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"The magnetic field at the center of a 50-turn coil of radius 15 cm is 0.60mT. find the current in the coil."
N=50, r = .15m, B = 6.0 * 10^-4 T, magnetic permeability = 4 * pi * 10^-7.

B = (mag.per. * N * I)/ L
However, I don't have L, which is the length. I do have r, the radius, but it's not in the equation... How do i solve this?
 
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This is not a solenoid, just a ring of wire. A hoola hoop.
 
then what does "a 50-turn coil" mean?
my book gives me the equation for finding the magnetic field in the center of a circular loop: B = (mag. per. * I)/(2r). But then how do I factor the "50-turn coil" in? Is this simply superfluous information?
 
Think about it: You have the formula for the field at the center of a single circular loop of current-carrying wire, so what would you expect the field to be for 50 of them combined?
 
50 times the strength I suppose...

well, that does work out:
1/50 B = (mag.per. * I)/(2r)
and solving for I, I get: I = 2.9A, which is the right answer.

Thanks.
 

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