So far you've seen how to draw ray diagrams for flat and spherical mirrors. You have also learned how to calculate the image distance and magnification for spherical mirrors. Let's review what you've learned so far. First, let's look at the image characteristics of location and type.
Mirror Equation
\(\large\mathsf{ \frac{1}{f} = \frac{1}{s_o} + \frac{1}{s_i} }\)
...where f is the focal length, so is the object distance, and si is the image distance.
| Variable | Positive (+) | Negative (-) |
|---|---|---|
| f | concave | convex |
| si | real image | virtual image |
Now, let's look at image characteristic of size as compared to the original object or magnification.
Magnification
\(\large\mathsf{ M = \frac{h_i}{h_o} = \frac{-s_i}{s_o} }\)
...where M is the magnification, hi is the image height, ho is the object height, si is the image distance, and so is the object distance.
| M | Type of Image |
|---|---|
| Positive (+) | upright |
| Negative (-) | inverted |
| 0 < |M| < 1 | smaller than original |
| |M| > 1 | larger than original |
Make sure to include this information on your equation note card as you move forward with problem solving.
