Light, Shadows and Reflections

Why can't you see through a wall? Why do shadows stretch at sunset? 🌅

📖 Concepts

1Light and what we see→2Light travels in straight lines→3Transparent, translucent, opaque→4Shadows — size, shape, position→5Pinhole camera→6Reflection and mirrors→7Shadows at cosmic scale — eclipses→8Refraction — light bending at a boundary→9White light and rainbow colours→

🎯 Practice questions

The tier ladder: 🌱basic warms you up, ⚡regular is exam-paced, 🔥hard twists the same ideas. The 🏆olympiad tier matches the “Achievers” section of the real exam.