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初二的焦距怎么算
更新时间: 2021-02-09 19:31:49  

1、通过透镜的成像规律来计算焦距:1/f=1/u+1/v 。(f是焦距,u是物距,v是相距)。

2、对在空气中厚度为d,曲率半径为R1和R2的透镜,有效焦距为:1/f=(n-1)[1/R?-1/R?+(n-1)d/nR?R?] 此处n是透镜材料的折射率,数值1/f就是这个透镜的光学倍率,f是焦距。已知折射率n、曲率半径R就可根据公式求出焦距f。

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