Chapter 44: Problem 11

Question: An object is $O=20~{\rm cm}$ to the left of a thin diverging lens having a focal langth of $f=-30~{\rm cm}$. Where is the image formed? Obtain the image location both by calculation and by a ray diagram.

Solution:

$$I~=~{fO\over O-f}~=~{(-30)(20)\over(20+30)}~=~-12~{\rm cm}$$

i.e. $12~{\rm cm}$ in front of the lens.

INSERT FIGURE