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Science

Light - Reflection and Refraction

Introduction

Spherical mirrors, refraction, lenses, mirror/lens formulas, magnification, and power of lenses.

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Mirrors and Lenses

Concave mirror converges, convex diverges. R=2f. Mirror formula: 1/v+1/u=1/f. Refraction: Snell's law n1.sin(i)=n2.sin(r). Convex lens converges, concave diverges. Lens formula: 1/v-1/u=1/f. Power P=1/f dioptres.

Key Points

  • Mirror: 1/v+1/u=1/f; m=-v/u
  • Lens: 1/v-1/u=1/f; m=v/u
  • Power P=1/f (dioptre, f in metres)
  • Snell's law: n1.sin(i)=n2.sin(r)
  • R=2f for spherical mirrors

Quick Summary

  • Mirror: 1/v+1/u=1/f
  • Lens: 1/v-1/u=1/f
  • P=1/f dioptres; Snell's law for refraction
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Key Formulas

Mirror: 1/v+1/u=1/f; m=-v/u

Lens: 1/v-1/u=1/f; m=v/u

P=1/f; n=sin(i)/sin(r); R=2f

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