Live Optics Calculations
Real ImageProjection screen is modeled for real lens images only.
Refraction Parameters
Ray Optics Interactive Challenges
Test your understanding of geometric ray optics, ray diagrams, and image formation.
Predict Image Characteristics
Given a specific lens focal length and object distance, predict whether the image is Real/Virtual, Upright/Inverted, and Enlarged/Reduced.
Complete the Ray Diagram
An incident principal ray hits an optical element. Select where the refracted or reflected ray travels next.
Find the Focal Length
Given measured object and image distances on an optical bench, calculate the focal length in this ideal thin-lens model.
Identify Mystery Optical Element
Observe incoming and outgoing rays through a hidden box and identify the idealized lens or mirror from the stated ray behavior.
Geometric Ray Optics Educational Reference
Geometric optics models light propagation in terms of rays—straight lines along which light energy travels. This ray model is useful when wavelength-scale effects can be neglected; the bench further assumes paraxial rays and ideal thin lenses or spherical mirrors.
Convex (Converging) Lens
Thicker at the center than at the edges. Parallel light rays pass through and converge at the focal point $F$.
- $d_o > 2F$: Real, inverted, reduced image between $F$ & $2F$.
- $d_o = 2F$: Real, inverted, same size image at $2F$.
- $F < d_o < 2F$: Real, inverted, enlarged image beyond $2F$.
- $d_o < F$: Virtual, upright, enlarged image behind object.
Concave (Diverging) Lens
Thinner at the center than at the edges. Parallel light rays refract outwards as if emanating from the near focal point.
- Focal length $f$ is negative ($f < 0$).
- For a real object in this ideal model, the image is virtual, upright, and reduced.
- For the positive real-object distances used here, the virtual image lies between the lens and the incident-side focal point.
Model Scope & Physical Limits of Geometric Optics
This laboratory uses paraxial thin-lens and spherical-mirror geometric optics approximations. It is a teaching model, not an optical-design or metrology tool. Real systems can exhibit effects ignored here: