Question

In the adjacent diagram, AO is a ray of light incident on a rectangular glass slab.

(a) Complete the path of the ray till it emerges out of the slab.
(b) In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles i and r ?
(c) Mark angle of emergence by the letter e. How are the angles i and e related ?
(d) Which two rays are parallel to each other ?
(e) Indicate in the diagram the lateral displacement between the emergent ray and the incident ray. State one factor that affects the lateral displacement.

Answer 1

(a)
The complete path of incident ray in glass block is drawn in figure below:

(b)
Angle of incidence (i) and angle of refraction (r) are marked in part (a). Refractive index of glass is related to the angles as
$n=\frac{\sin i}{\sin r}$

(c)
Angle of emergence (e) is marked in part (a). It is equal to the angle of incidence.
$i=e$

(d)
Incident ray and emergent ray are parallel to each other. This is because the bending is equal and opposite at the two surfaces.

(e)
Lateral displacement is indicated in the figure by XY. It depends on the thickness of the glass slab, refractive index, and the thickness of the glass slab.