Question

With the help of a ray diagram, show that a straw appears bent when it is partly dipped in water and explain it.

Hint:

The apparent bending of a straw in water is due to the refraction of light at the water-air interface.

Answer 1

When light travels from one medium to another (such as from water to air), the change in speed causes the light rays to bend at the interface. This bending of light makes the straw appear broken or bent at the surface of water. The light rays from the part of the straw submerged in water are refracted at the water-air interface, making the submerged part appear displaced from the rest of the straw.