JEE Main & Advanced Physics Ray Optics Question Bank Refraction of Light at Plane Surfaces

  • question_answer
    Refractive index of air is 1.0003. The correct thickness of air column which will have one more wavelength of yellow light \[\left( 6000\text{ }{AA} \right)\] than in the same thickness in vacuum is  [RPMT 1995]

    A) 2 mm                                       

    B) 2 cm

    C) 2 m                                           

    D) 2 km

    Correct Answer: A

    Solution :

    For vacuum \[t=n\,{{\lambda }_{o}}\]                                 .....(i) For air \[t=(n+1)\,{{\lambda }_{a}}\]                                       .....(ii) From equation (i) and (ii) \[t=\frac{\lambda }{\mu -1}=\frac{6\times {{10}^{-7}}}{1.0003-1}\] \[\left( \mu =\frac{{{\lambda }_{o}}}{{{\lambda }_{a}}} \right)\] \[=2\times {{10}^{-3}}m\] = 2mm.


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