Lesson Plan

• Describe how a plane mirror forms a virtual image.
• Explain the law of reflection and its role in image formation.
• Identify the image characteristics: same size, same distance, upright, laterally inverted, and virtual.
• Construct accurate ray diagrams to locate the image behind a plane mirror.
• Solve exam‑style questions on image position, size and nature.

• Plane mirror (or mirror model)
• Ray‑diagram worksheets
• Whiteboard and markers
• Projector with slide of ray diagram
• Ruler / protractor
• Exit‑ticket cards

Begin with a quick “mirror mystery” demonstration where a student’s reflection appears behind the mirror, sparking curiosity. Review the law of reflection and ask learners to predict where the image will form. State that by the end of the lesson they will be able to draw and explain the image formation and its key features.

1. Do‑now (5'): Students sketch a simple ray diagram for a given object‑mirror distance.
2. Mini‑lecture (10'): Review law of reflection, introduce virtual image concept, and show a teacher‑led diagram.
3. Guided practice (12'): In pairs, students complete the worksheet steps (draw incident rays, apply law, extend reflected rays, locate image).
4. Class discussion (8'): Groups share diagrams; teacher highlights characteristics (size, distance, orientation, virtual).
5. Exam question practice (10'): Students answer a typical IGCSE question individually, then check with peers.
6. Check for understanding (5'): Quick exit ticket – write one characteristic of the image and why it occurs.

Recap the steps of image formation and the five key characteristics. Collect exit tickets to gauge understanding and assign a short homework task: draw a ray diagram for a new object distance and label all features.