Before you read this, I suggest you read post 22.6. In post 22.6, we looked at the path taken by a ray when it is reflected by a concave surface. We looked at two types of concave surface. In the first, a section of the surface was the arc of a circle; in the second,… Continue reading 22.7 The caustic curve

Before you read this, I suggest you read post 22.4. When I wrote about reflection in post 22.4, I concentrated on reflection of light by a mirror. Concave mirrors are useful but the more familiar applications of reflection at concave surfaces involve focussing radio waves and microwaves from distant objects. Examples include radio-telescopes, receivers for… Continue reading 22.6 Reflection at concave surfaces – the satellite dish

Before you read this, I suggest you read post 22.4. In post 19.21, we saw that a ray of light passing from air into glass (or any other dense, transparent medium) is bent towards the normal to the interface between them, as shown in the picture above. In this picture A is a point in… Continue reading 22.5 Total internal reflection