Find the percent differences. Table 1 f = 100 mm Object distance Image distance 1 cm cm do di cm cm 20 20.6 76.9 11.8 11.6 77.1 57.8 12.5 52.8 13.1 12.1 53.8 64 12.1 11.8 64.3 33.3 14.3 14.2 33.2 Questions: 1. Is the image formed by the lens erect or inverted? 2. Is the image real or virtual? How do you know? 3. Explain why, for a given screen-object distance, there are two positions where the image is in focus. 4. Why is the magnification negative