A ray of light passes through four transparent media with refractive indices mu_1,mu_2,mu_3 and mu_4 as shown in the figure. The surfaces of all media are parallel. If the emergent ray CD in parallel to the incident ray AB we must have

A ray of light passes through four transparent media with refractive i

1.	A ray of light passes through four transparent media with refractive indices mu_1,mu_2,mu_3 and mu_4 as shown in the figure. The surfaces of all media are parallel. If the emergent ray CD in parallel to the incident ray AB we must have
Answer» SOLUTION :APPLYING snell.s law at B and C `MU sin i`= constant or `mu_1 sin i_B= mu_4 sin i_C` But `AB\|\|CD` `therefore i_B=i_C or mu_1=mu_4`