Magnetostatic Problems: Calculating Inductance and Loop Internal Inductance

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The discussion focuses on calculating inductance in various magnetostatic scenarios, including a coaxial cable with an inhomogeneous material, parallel copper wires, and a circular loop. The self-inductance of the coaxial cable is derived using a specific formula, while the inductance for the copper wires is calculated with given dimensions and separation. Participants express confusion over the calculations, particularly regarding the coaxial cable's answer and the inductance of the parallel wires. There is also a note about the forum's LaTeX functionality being broken, impacting the ability to share complex equations. Assistance is requested for solving these magnetostatic problems.
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1) Calculate the self-inductance of a coaxial cable of inner radius a and outer radius b. The inner conductor is made of an inhomogenous material having u = 2u0/(1+r)
Answer : u0L/8pie + u0L/pie (ln(b/a) - ln((1+b)/(1+a)))

2) Two #10 copper wires(2.588 mm in diameter) are placed parallel in air with a separation distance d between them. If the inductance of each wire is 1.2uH/m, calculate
(a) L(in) and L(ext) per meter for each wire
(b) The separation d
Answer : (a)0.05, 1.15 uH/m, (b) 40.79cm

3) A conductor of radius a is bent into a circular loop of mean radius r. If r = 10cm and 2a = 1cm, calculate the internal inductance of the loop.
Answer : 31.42nH

Really can't the number 1 answer. I get a^3 in my answer. Number 2 no idea since L = L(in) + L(ext). As well as number 3.



Thank you.
 

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cannot use Latex code anymore?
 
Apparently they changed servers and LaTeX broke but they're working on fixing it.
 
anyone can help me on these magnetostatic problems? I'm stucked ..
 
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