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

In which material do you think light rays travel faster-glass or air?

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

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

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 _____