In figure, AO is the ray of white light falling on a prism PQR. Complete the diagram till the light emerges out from the prism and falls on the screen.

What is a prism? Draw a ray diagram to show the refraction of a light ray through a prism.

A ray of white light falls on a prism. Draw a ray diagram to show that the prism disperses the white light.

What is a mirage? Give a reason for its formation.