物理光学干涉衍射A thin film of oil (n=1.25) is located on a smooth wet pa_英语解答

物理光学干涉衍射
A thin film of oil (n=1.25) is located on a smooth wet pavement.When viewed perpendicular to the pavement,the film appears to be predominantly red(λ=640nm) and has no blue color (λ=512nm).How thick is the oil film?
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人气：248 ℃　时间：2020-06-13 20:31:30

解答

楼上翻译有小错,应该是“无蓝色颜色(λ=512nm)”翻译全文如下：
薄膜油n=1.25,位于光滑的湿路面上.当对路面垂直观察时,看起来主要是红色(λ=640nm),并且没有蓝色(λ=512nm).求油膜是多厚?
垂直观察时,红光相长,蓝乐相消,由于上下反射面都有半波损失,因此光程差为
L=2nd
按题意,有
L=k1λ1=(k2+1/2)λ2
其中k1,k2均为整数
从k1=1开始依次尝试,可知k1=2,k2=2时上式成立,且L=1280nm
故油膜厚
d=512nm