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.

When a light ray passes from air into glass, what happens to its speed? Draw a diagram to show which way the ray of light bends.

Explain why, a stick half immersed in water appears to be bent at the surface. Draw a labeled diagram to illustrate your answer.

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

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