A transparent slab of thickness d has a refractive index n (z) that increases with z. Here z is the vertical distance inside the slab, measured from the top. The slab is placed between two media with uniform refractive indices n1 and n2 (> n1), as shown in the figure. A ray of light is incident with angle θi from medium 1 and emerges in medium 2 with refraction angle θf with a lateral displacement l.
Which of the following statement (s) is (are) true?
(A) n1 sinθi = n2 sin θf
(B) n1 sinθi = (n2 - n1) sin θf
(C) l is independent of n2
(D) l is dependent on n (z)