🪞 Mirrors & Lenses

Geometric optics ray diagram. Choose a lens or mirror type, adjust focal length and object distance, and watch three principal rays form a real or virtual image. Uses the thin-lens equation 1/f = 1/d_o + 1/d_i.

Optical Element

Focal length f 120 px Object distance d_o 200 px Object height 60 px

Image Properties

Image dist d_i—

Magnification—

Image height—

Real · Inverted

Rays: 🔴 Parallel → through F′. 🟢 Through centre → straight. 🔵 Through F → parallel after lens. Dashed rays = virtual extensions.