How can I find the number of turns in a solenoid winding?

AI Thread Summary
To determine the number of turns in a solenoid winding, the mutual inductance formula can be applied, but it requires known values for the solenoid's inductance and dimensions. The inductance of the solenoid is given as 30mH, with a length of 0.4m and a diameter of 0.1m. The resistance of the coil is 5.0 ohms, and the mutual inductance is 60μH. The current in the solenoid is 0.3A, decreasing at a rate of 2.5A/s, which is relevant for calculating induced emf and flux linkage. The discussion emphasizes the need to clarify which values are unknown to solve for the number of turns effectively.
kdawg4
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A 30mH solenoid inductor is wound on a form 0.4 m in length and 0.1 m in diameter. A coil is tightly wound around the solenoid at its center. the coil resistance is 5.0 ohms. The mutual inductance of the coil and solenoid is 60μH. At a given instant, the current in the solenoid is 0.3A and is decreasing at a rate of 2.5A/s.


a) Find the number of turns in the winding of the solenoid
b) Find the induced emf at the given instant.
c) At the given instant, the flux linkage N(phi) for the solenoid is...


Hey guys, really need a nice simple answer here, thank you...I'm new to the forum by the way :D
At first I used the formula mu(n1)(n2)A/L equals the mutual inductance but now I am stumped since you have 2 unknowns and I don't know how to find one of them
 
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kdawg4 said:
A 30mH solenoid inductor is wound on a form 0.4 m in length and 0.1 m in diameter. A coil is tightly wound around the solenoid at its center. the coil resistance is 5.0 ohms. The mutual inductance of the coil and solenoid is 60μH. At a given instant, the current in the solenoid is 0.3A and is decreasing at a rate of 2.5A/s.

a) Find the number of turns in the winding of the solenoid
b) Find the induced emf at the given instant.
c) At the given instant, the flux linkage N(phi) for the solenoid is...


Hey guys, really need a nice simple answer here, thank you...I'm new to the forum by the way :D
At first I used the formula mu(n1)(n2)A/L equals the mutual inductance but now I am stumped since you have 2 unknowns and I don't know how to find one of them

Hi kdawg4, Welcome to Physics Forums.

Which part of the problem are you working on? Do you know the formula for the inductance of a solenoid?
 


I am currently workingon all three, and yes I know the formula for the inductance of a solenoid
 


kdawg4 said:
I am currently workingon all three, and yes I know the formula for the inductance of a solenoid

Okay then, for part (a), what values in the formula for the inductance of the solenoid are unknowns (values that you haven't been given)?
 

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