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 incident with angle
θi from medium 1 and emerges in medium 2 with refraction angle
θf with lateral displacement
l.
Which of the following statement(s) is (are) true?