# Thin-Lens / Mirror Equations

- Author:
- William C. Evans

- Topic:
- Equations

## Thin-Lens / Mirror Equations

This applet shows the thin-lens/mirror equation, and magnification equation, graphed. The focal length is adjustable, as is the object distance. Moving the object-distance slider will move an indicator point on both graphs (image distance and magnification).
A text display of the characteristics of the image shows real/virtual, inverted/upright, larger/smaller/equal. These are discussed in the attached PDF, which also provides the equations being graphed.
A companion applet shows a principal-ray diagram, which can be useful to use along with this applet to understand how the image varies as the focal length and object distance are varied.