n0n0,有半波损失,光程差L=2nd+λ/2
干涉相长条件L=2nd+λ/2=Kλ,K=1, 2, 3,.
干涉相长条件的波长λ=2nd/(K-1/2)=1769.6nm,589.9nm,353.9nm,252.8nm.
只有589.9nm光干涉相长,油膜呈黄颜色