※ 引述《aacvbn ( 姿勢+)》之銘言：
: 96雲科光電所 http://www.lib.yuntech.edu.tw/exam_new/96/de.pdf
: [最末頁第五題]
: Find the resistance between two concentric spherical surfaces
: of radii R1 and R2 (R1<R2) if the space between the surfaces
: is filled with a homogenous and isotropic material having a
: conductivity σ.
令中央灌入電流 I , J=I/(4πR^2) , E = J/σ=I/(4πR^2)σ
R2 R2 I *[1/R1-1/R2]
v = ∫E dR = ∫ I/(4πR^2σ) dR =-I/(4πRσ)︳= ______________
R1 R1 4πσ
1/R1-1/R2
resistance = V/I = __________
4πσ
有錯誤請多多指正..
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 118.171.102.115