What Is the Correct Calculation for Current in a Solenoid?

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To calculate the current in a solenoid with a length of 0.16 m and 130 turns producing a magnetic field of 2.0 mT, the formula B = μNI/L is used. The user initially substituted values but incorrectly used the permeability constant μ as 2e-7 instead of the appropriate value for free space, which is approximately 4πe-7. Additionally, the user failed to convert the magnetic field strength from milliTesla to Tesla, which is necessary for accurate calculations. After correcting these errors, the current can be accurately determined. Proper unit conversion and the correct permeability constant are crucial for solving this problem.
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Homework Statement



A solenoid is 0.16 m long and consists of 130 turns of wire. At its center, the solenoid produces a magnetic field with a strength of 2.0 mT. Find the current in the coil.


Homework Equations


B=μNI/L B=strengh of magnet N=number of loops I= current and L=lengh μ is the constant 2e-7

The Attempt at a Solution


I plugged in 2mT=(2e-7)(130)(I)/.16m
I got 2mt=(.0001625)(I). I then did 2/.0001625 and got the current to equal 12,307.69 but it isn't right.What did I do wrong?
 
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hi tomsolo, and welcome to physicsforums :)
Ah, it looks almost correct, but there are two things that I'm not sure about. Why is μ equal to 2E-7 ? In free space it is roughly equal to 13E-7 Also, on the last line, you've got 12,307.69 but you still need to take into account that the magnetic field was in milliTesla.
 

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