如图所示,一储油圆桶,底面直径与桶高均为 [tex=0.571x1.0]hXwI6nnMJ2kxGYNl2OSrPw==[/tex]. 当桶内无油时,从某点 [tex=0.786x1.0]b4HkKtHXeHofHX/gJc8Agg==[/tex] 恰能看到桶底边缘上的某点[tex=0.786x1.0]9uq8NvjklzVl/yrUHrVKTg==[/tex]. 当桶内油的深度等于桶高一半时,在 [tex=0.786x1.0]b4HkKtHXeHofHX/gJc8Agg==[/tex] 点沿 [tex=1.571x1.0]mCjAngcIqtveplNftuY0BQ==[/tex] 方向看去,看到桶底上的 [tex=0.714x1.0]YiLkHgl7MlxE+QjUplQUKA==[/tex] 点, [tex=2.571x1.286]JYxLfh6WrvwRghLFJIa2Zw==[/tex] 相距[tex=0.786x2.429]kAcXn7gNlgRh3l7CRLe9UA==[/tex]. 由此可得油的折射率以及光在油中传播的速度为[img=239x271]17a5c49a596b000.jpg[/img] 未知类型：{'options': ['[tex=2.0x2.643]MGvFLG/cFmQBpt4kLFYFs3W32qybliR61sYba9lITcI=[/tex], [tex=7.143x1.429]T1+ET5DDIBdigRf6WNiWwUVEUaeZ4g0omZgFvzQaaQ+o+tOuGE6JcGg7XMJmOiW6[/tex]', '[tex=2.0x2.643]VMzgRsJdxt/4l97g4g2SRUlt6pgEjnWhWyzxsdgblCE=[/tex],\xa0[tex=7.143x1.429]T1+ET5DDIBdigRf6WNiWwUVEUaeZ4g0omZgFvzQaaQ+o+tOuGE6JcGg7XMJmOiW6[/tex]', '[tex=2.0x2.643]VMzgRsJdxt/4l97g4g2SRUlt6pgEjnWhWyzxsdgblCE=[/tex], [tex=7.929x1.429]WVEgpLI1qltekghCB0P8FcGyFeoNFoH7/1k5zpKfnX7L5v68PvY7R2/K+Gf/FVuW[/tex]', '[tex=2.143x2.643]MGvFLG/cFmQBpt4kLFYFs3W32qybliR61sYba9lITcI=[/tex], [tex=7.929x1.429]WVEgpLI1qltekghCB0P8FcGyFeoNFoH7/1k5zpKfnX7L5v68PvY7R2/K+Gf/FVuW[/tex]'], 'type': 102}