Name the phenomenon due to which a pencil partly immersed in water and held obliquely appears to be bent at the water surface.

A coin in a glass tumbler appears to rise as the glass tumbler is slowly filled with water. Name the phenomenon responsible for this effect.

With the help of a labeled diagram, explain why a tank full of water appears less deep than it actually is.

With the help of a diagram, show how when light falls obliquely on the side of a rectangular glass slab, the emergent ray is parallel to the incident ray.

Show the lateral displacement of the ray on the diagram.