JEE Main & Advanced Sample Paper JEE Main Sample Paper-38

  • question_answer A glass slab has the left half of refractive index \[{{n}_{1}},\] and the right half of\[{{n}_{2}}=3{{n}_{1}}\]. The effective refractive index of the whole slab is

    A)  \[\frac{{{n}_{1}}}{2}\]                       

    B)  \[2n\]

    C)  \[\frac{3{{n}_{1}}}{2}\]                             

    D)  \[\frac{2{{n}_{1}}}{2}\]

    Correct Answer: C

    Solution :

     Total time taken to travel distance d is : \[\frac{d}{2{{n}_{1}}}+\frac{d}{2{{n}_{2}}}=d\left( \frac{{{n}_{1}}+{{n}_{2}}}{2{{n}_{1}}{{n}_{2}}} \right)=\frac{d}{{{n}_{eff}}};\]\[{{n}_{2}}=3{{n}_{1}}\Rightarrow {{n}_{eff}}=\frac{3}{2}{{n}_{1}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner