Optics: The Lens Power Cheat Sheet!

Struggling with lens power calculations? What if you could remember the relationships instantly, without memorizing formulas?

Subject: optics • Classes: 6–12 • Difficulty: intermediate (9-10)

The Trick

Power of a lens (P) is the reciprocal of its focal length (f) in meters: $P = \frac{1}{f}$. Converging lenses have positive power (positive f), and diverging lenses have negative power (negative f). This works because power measures how strongly a lens converges or diverges light. Higher power = shorter focal length = stronger bending.

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