What is the inductance of a solenoid with a soft iron core?

In summary, the conversation discusses the calculation of inductance in milli-henry (mH) for a solenoid with 140 turns uniformly wrapped around a soft iron core. The formula L=(uN^2A)/length is used, with a magnetic permeability of 750 Uo (mue sub-knot), a diameter of 10.0m, and a length of 9.00cm. The correct calculation for inductance is 1.15E6 mH. There were two errors in the initial calculation, an extra 0.09m on top and a missing μ0.
  • #1
pattiecake
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A solenoid has 140 turns uniformly wrapped around a soft iron core, which has a magnetic permeability =750 Uo (mue sub-knot) diameter of 10.0m and a length of 9.00cm.

What is the inductance in milli-henry (mH)?

Did I set this up right? Using L=(uN^2A)/length, you get:

(750*140^2*pi.005m^2*.09m)/.09m = 1.15E3 Henry = 1.15E6 Milli-Henry

I think I made a conversion error somewhere. If not, why would they ask for the inductance in milli-henry, and not kilo-henry? :confused:
 
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  • #2
Your formula for L is correct. In your arithmetic I see two errors: an extra 0.09m on top, and--most importantly--a missing μ0. The permeability is μ = 750 μ0; μ0 = 4π10-7 N/A2.
 
  • #3
ohhhhhhhhhhh! Thanks!
 

1. What is the definition of inductance?

Inductance is the property of an electrical circuit that causes an electromotive force to be generated in response to a change in the current flowing through the circuit.

2. How is inductance measured?

Inductance is measured in units of Henry (H), named after Joseph Henry who discovered the phenomenon of inductance. It can be measured using an inductance meter or by calculating the ratio of voltage to current in a circuit.

3. What factors affect the inductance of a solenoid?

The inductance of a solenoid is affected by the number of turns of wire, the length and diameter of the solenoid, and the material of the core. It also depends on the frequency and current passing through the solenoid.

4. How does inductance impact the behavior of a solenoid?

Inductance causes a solenoid to resist changes in current, which results in the generation of a magnetic field. This magnetic field can be used to create motion or to store energy in the form of an induced current.

5. Can the inductance of a solenoid be changed?

Yes, the inductance of a solenoid can be changed by altering its physical properties, such as the number of turns or the material of the core. It can also be changed by using external components, such as capacitors, to affect the frequency and current passing through the solenoid.

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