1. By varying the location of the object, lens, and screen, obtain object distance and image distance data for five more points and fill in the chart below. (Remember: d_i and d_o are the distances from the lens to the object and image, respectively, NOT the location on the track.) d_i vs d_o for 10 cm lens:

do	di	1/do	1/di
(cm)	(cm)	(cm-1)	(cm-1)
15
20
30
40
50
60

Note what happens to the size of the image as the object distance increases.

1. Return the light to the 10 cm mark and the lens to the 25 cm mark on the track. Gradually move the lens closer to the light source, while still moving the film to maintain a focused image. When it reaches the 20 cm mark, can you find a position for the screen where the image is in focus?