(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I have two homework problems, both of which require me to solve the equation for the capacitance of a capacitor for the inner radius of the capacitor (one cylindrical, one spherical). This shouldn't be a problem, but I think my algebra is screwy.

a = inner radius

b = outer radius

C = capacitance

h = height of capacitor

2. Relevant equations

Capacitance of a Spherical Capacitor:

(i) C=4[tex]\pi[/tex][tex]\epsilon_{0}[/tex]ab / (b-a)

Capacitance of a Cylindrical Capacitor:

(ii) C=2[tex]\pi[/tex][tex]\epsilon_{0}[/tex]h / ln(b/a)

3. The attempt at a solution

My attempts at solving these for a are as follows:

(i) a = b*C / (C + 4*[tex]\pi[/tex]*[tex]\epsilon[/tex]*b)

(ii) a = b / e[tex]^{(2*\pi*\epsilon*h / C)}[/tex]

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# Homework Help: Solving Spherical and Cylindrical Capacitors for Inner Radii

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