[題目] 普物電學

[akw102000 (大白)]

[領域]電位與電位能

[來源] 課本習題

[題目]http://0rz.tw/3f2Bb
      A Geiger counter is used to detect charged particles emitted by
      radioactive nuvclei. It consists of a thin, positively charged
      central wire of radius Ra surrounded by a concentric conducting
      cylinder of radius Rb with an equal negative charge. The charge per
      unit length on the inner wire is λ(unit C/m). The cylindrical
      assembly is filled with lowpressure inert gas. Charged particles
      ionize some of these gas atoms; the resultinig free electrons are
      attracted toward the central wire. If the radial electric field is
      strong enough, the freed electrons gain enough energy to ionize other
      atoms, causing an "avalanche" of electrons strike the central wire,
      generating an electric"signal." Find the expression for the electric
      field between the wire and cylinder, and show that the potential
      difference between Ra and Rb is Va-Vb=ΔV=(λ/2πε)ln(Ra/Rb)

[瓶頸] 其實題目我看不太懂orz。好像是說中間那條wire和外面的cylinder中間
       會有一個夠強的電場解離周圍的氣體分子。那跟他要我證明的式子有什麼
       關係呀？而且我不會求柱狀跟管狀的電場or電位...


--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 140.113.187.150
→ mathfeel:高斯面求電場再求電勢差
→ akw102000:可是外面的cylinder 跟中間的wire 電量加起來不是0嗎？
→ mathfeel:cylinder以外是，以內不是