Question

A thin layer of water is transparent but a very thick layer of water is
A) Translucent
B) Opaque
C) Most transparent
D) None of the above

Answer 1

Hint: A thin layer of water acts as a very fine film between the viewer and object. But in the thick layer, the view is not transparent as there is a lateral shift but it is not said to be opaque because in opaque nothing is visible.

Complete step by step answer:
Step 1:
When a ray of light is incident obliquely on a parallel, Sided glass slab the emergent ray shifts laterally. The perpendicular distance between the direction of the incident ray and emergent ray is called lateral shift
A lateral shift is a position of the side gilded spine. Lateral shift exists when the vertebra above is laterally flexed to right or left in relation to the vertebra below, carrying the trunk with it. As a result, the upper trunk and shoulders are shifted to the right or left.
Step 2:
Lateral shift depends on thickness: The lateral displacement is directly proportional to the thickness of the glass slab. When the light enters a glass slab, the light rays are refracted. Now, the lateral displacement is the final distance between the incident ray and the emergent ray.

Hence the water will be translucent.

Additional information:
The Refractive index of a material is its power to deviate an incident light ray from its original path upon entering the material. More is the refractive index, more is the deviation and hence the lateral shift. Hence we can say the lateral shift is directly proportional to the refractive index
Movement is in the pattern two steps forward, one step back 3 seconds in, 2 seconds off. When a lateral shift is overcorrected it can be maintained for a few seconds.
The shift is seen in the water when we put a coin in the glass
Or fish in ponds seen in different depths etc.

Note:
Lateral shift depends on the perpendicular distance between the incident ray and the emergent ray gives us the lateral shift. It depends on the angle of incidence, refractive index, and thickness of the refractive medium.