Geometric Optics

Geometric Optics

Lens Formula

$$ \large \frac{1}{\text{O}} + \frac{1}{\text{I}} = \frac{1}{\text{F}}$$

Focal Lengh (F)

(+): Convergent

(-): Divergent

Lensmaker's Equation

$$ \large \frac{1}{f} = (n-1) \left( \frac{1}{R_1} - \frac{1}{R_2} \right) $$


$f$: focal length of the lens,

$n$: refractive index of the lens material,

$R_{1}$: radius of curvature (with sign, see below) of the lens surface closer to the light source,

$R_{2}$: radius of curvature of the lens surface farther from the light source.

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