JCECE Medical JCECE Medical Solved Paper-2014

  • question_answer
    When the angle of incidence is \[{{60}^{o}}\] on the surface of a glass slab, it is found that the reflected ray is completely polarised. The velocity of light in glass is

    A) \[\sqrt{2}\times {{10}^{8}}m{{s}^{-1}}\]

    B)  \[\sqrt{3}\times {{10}^{8}}m{{s}^{-1}}\]

    C)  \[2\times {{10}^{8}}m{{s}^{-1}}\]

    D)  \[3\times {{10}^{8}}\,m{{s}^{-1}}\]

    Correct Answer: B

    Solution :

     Refractive index of glass \[{{\mu }_{g}}=\tan \,{{O}_{P}}\] where,\[{{O}_{P}}=\] polarising angle \[{{\mu }_{g}}=\tan {{60}^{o}}=\sqrt{3}\] \[{{\mu }_{g}}=\frac{c}{{{v}_{g}}}\] \[\frac{c}{{{v}_{g}}}=\sqrt{3}\] \[{{v}_{g}}=\frac{3\times {{10}^{8}}}{\sqrt{3}}=\sqrt{3}\times {{10}^{8}}\,m/s\]


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