[问答题]
A drop of oil on a pond appears3 o2l1 wa6uujogd;z/p bright at its edges, where its thi jtp un0fikx) : 1v(1dh-ltkead 45o;pckness is much less than the wavelengths of visible light. What can you say about the index of refractiox-thv i 0);ppkd(aj1dl:o1nek 45u tfn of the oil?
