An image is 4.0 mm in front of a convex lens with focal length of magnitude 5.0 mm.Where is the object for this image?

Question

Quizplus · Accepted Answer

Using the lens equation $ \frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i} $, where $f$ is the focal length, $d_o$ is the object distance, and $d_i$ is the image distance. Given $f = 5.0 \, mm$ and $d_i = -4.0 \, mm$ (negative because the image is on the same side as the object for a convex lens), solving for $d_o$ gives approximately $d_o = 20 \, mm$, indicating the object is in front of the lens.

An Image Is 4