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Physics

Light Path and Fermat's Principle

Quick fact

Fermat's principle, formulated by Pierre de Fermat in 1650, not only explained the law of reflection but also correctly predicted the bending of light in refraction, stating that light follows the path of least time—a concept that later influenced the development of the principle of least action in mechanics.

Why this is interesting

You know light travels in straight lines, but have you ever wondered why it takes a particular path when it reflects off a mirror or bends through glass? It's not the shortest distance—it's something more elegant.