How Much Current Is Needed for a Solenoid to Generate a Specific Magnetic Field?

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To determine the current needed for a solenoid to generate a specific magnetic field, the relevant equation is B = μ₀ nI, where 'n' represents the number of turns per unit length. For a 50.0-cm long solenoid with 975 turns, 'n' is calculated as N/L, which requires using the length of the solenoid while ignoring the diameter. The diameter is not directly used in the calculation of 'n' but is important for ensuring the solenoid is long enough relative to its diameter. The discussion emphasizes the importance of correctly applying the formula for a long solenoid to achieve the desired magnetic field strength. Understanding these parameters is crucial for accurate calculations in electromagnetism.
jena
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Hi,

My Question:

A 50.0-cm long solenoid 1.25cm in diameter is to produce a field of 0.385 T at its center. How much current should the solenoid carry if it has 975 turns of the wire?

I know that I have to use this equation:

B = \mu _0 nI


where I'm stuck at is with the length do I used the how long it is with the diameter or do i just ignore the diameter :confused:

please help

Thank You :smile:
 
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1
The formula you have written is for a long solenoid such that L >>R, to insure this, I think the dimeter is given, otherwise you have to use general formula for the field.
2
In this formula 'n' is the number of turns per unit length n = N/L.
 
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