Lenses

Ray diagrams and images

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Converging lenses bend parallel rays through the focal point.
• $\frac1f = \frac{1}{d_o} + \frac{1}{d_i}$ and $m = -\frac{d_i}{d_o}$.
• Beyond F: real, inverted image. Inside F: virtual, upright, magnified image.

Steps

1. Burning point
2. Ray diagrams
3. The thin lens equation
4. Where’s the image?
5. Same size
6. Magnifying glass