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 ${\mathrm{\theta }}_{\mathrm{i}}$ from medium 1 and emerges in medium 2 with refraction angle $\mathrm{\theta }$_f with a lateral displacement $l$ .
 

Which of the following statement(s) is(are) true?