'Optics' is a section of physics that requires you to construct optical ray diagrams.

These have to be drawn very precisely. See this page for details on the symbols used.

A reflected ray is the ray that 'bounces off' the boundary between two optical media (but never use that term in an exam - always say 'reflects').

It is formed according to the Law of Reflection... see the diagram below...

The angle of incidence is the angle between the normal and the incident ray.

The angle of reflection is the angle between the normal and the reflected ray.

The Law of reflection states that the angle of incidence equals the angle of reflection.

The incident ray and the reflected ray and the normal are all in the same plane.


Click here to see a page on an experiment to investigate the law of reflection.

There are two types of reflection you should know about.

Specular reflection happens from smooth surfaces - the surface reflects all light which arrives from a given direction at the same angle - obeying the Law of Reflection and producing a clear sharp reflection image,


Diffuse reflection happens when the surface is not smooth - light is reflected in a broad range of directions and produces a 'fuzzy' blurred image.

The formation of an image in a plane mirror

The vidclip below will lead you through how to draw a ray diagram of the reflection of a point object in a plane mirror - a frequent subject set in GCSE examination questions....

This vidclip takes you through how to construct a ray diagram to illustrate the nature the image in a plane mirror - that it is virtual, ertect, laterally inverted and that each image point is formed as far behind the mirror as the corresponding object point is in front.  

Now revise the topic from flash cards I have written for:

Optics questions GCSE Standard

Drawing a plane mirror diagram (transcript for videos)

Drawing ray diagrams

Convex Mirrors - ray diagram summary

Convex Mirrors - Uses

Concave Mirrors

Concave Mirrors - constructing a ray diagram

Concave Mirrors - Uses