question_answer

A ray of light posses through four transparent media with refractive indices \[{{\mu }_{1}},\,{{\mu }_{2}},{{\mu }_{3}}\] and \[{{\mu }_{4}}\] as shown in the figure. The surface of all medium are parallel if the emirgent ray CD is parallel to the incident ray AB, then:                                    

A)  \[{{\mu }_{1}}={{\mu }_{2}}\]                

B)  \[{{\mu }_{2}}={{\mu }_{3}}\]

C)  \[{{\mu }_{3}}={{\mu }_{4}}\]                

D)  \[{{\mu }_{4}}={{\mu }_{1}}\]