K323 / 2027

Chapter 12

Light

Ray diagrams show where light travels and help explain where an image appears.

Use the ray path, angles and image evidence to explain an optical situation.

Includes reflection, refraction, total internal reflection, optical fibres and real and virtual lens constructions. For K323 (2027) / 6091 (2026).

Start readingRevision summaryRead whole chapter

Choose a topic

  1. Reflection and plane mirrors

    Measure angles from a normal and locate a plane-mirror image using reflected rays.

  2. Refraction and refractive index

    Trace light across boundaries and calculate angles and speed using the stated media.

  3. Critical angle and optical fibres

    Explain the conditions for total internal reflection and how fibres guide light.

  4. Converging action and focal length

    Identify a principal focus and measure focal length from the lens centre.

  5. Real and virtual images

    Construct lens ray diagrams and explain image size, orientation and screen formation.