Why does a ray of light bend when it travels from one medium to another?

Which phenomenon of light makes the water to appear shallower than it really is?

State whether the following statement is true or false: Refraction occurs because light speeds up in denser materials.

Fill in the following blanks with suitable words:

(a) Light travelling along a ____ is not refracted.

(b) Light bends when it passes from water into air. We say that it is _____

What is meant by ‘refraction of light’? Draw a labeled ray diagram to show the refraction of light.