Snell's Law of Refraction: Light crossing medium boundaries satisfies $n_1 \sin\theta_1 = n_2 \sin\theta_2$. Total internal reflection occurs when angle of incidence exceeds critical angle $\theta_c = \arcsin(n_2/n_1)$.
Thin Lens & Mirror Equation: Object distance $d_o$, image distance $d_i$, and focal length $f$ satisfy $\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}$. Linear magnification is $M = -\frac{d_i}{d_o} = \frac{h_i}{h_o}$.
Lens Power & Eye Accommodation: Optical power $P = \frac{1}{f\text{ (m)}}$ (diopters). Ciliary muscles adjust crystalline lens curvature to focus light onto the retina.
Operating Instructions: Use sidebar tab switcher to explore Refraction/Reflection, Thin lenses and curved mirrors, Human eye vision correction, and Lens power.