1. Introduction: The Steel Plate on the Kitchen Shelf
Go to your kitchen. Pick up a steel plate — the kind you eat rice and dal from every day. Hold it so the tubelight falls on it. You will see a blurry version of your face.
Now hold a mirror instead. Same light, same angle. Now you see a sharp, clear image of your face.
Both surfaces are bouncing light back to your eyes. Both are doing "reflection." But the steel plate gives you a fuzzy blob, while the mirror gives you a photograph-sharp image.
Why?
The answer is not just "one is shiny and one is not." That describes what you see — it does not explain it. The real answer sits inside two precise rules that light follows when it bounces. These rules are called the laws of reflection, and they work on every surface — mirror, steel plate, water, even the wall behind you.
You met these laws briefly in earlier classes. Now we go deeper — because without them, you cannot solve a single question on mirrors or lenses.
Stop scrolling. Try it in your head before reading on: can you state the law of reflection from memory? One sentence.