Question

When a thick glass slab is placed over some printed material, the letters appear to be raised. Why? Also draw a ray diagram for the following.​

Answer 1

Answer:

The letters appear raised because of a phenomenon known as refraction. When light travels from one medium to another, it bends (either towards or away from the normal). This happens because different media have different densities and thus, the speed of light is different in each one of them. This causes the light to slow down or speed up, depending on the medium. Note that refraction takes place at the interface of two media, air and glass in this case. Also note that refraction only takes place when the light is incident obliquely to the medium and not along a normal drawn to it.

Explanation: