(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

For a lens with a focal length f, find the smallest distance possible between the object and its real image.

2. Relevant equations

1/s + 1/s' = 1/f

3. The attempt at a solution

I tried plugging in different numbers for the solution, but I'm not sure how to reach the solution..

The answer is s + s' = 4f

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# Homework Help: Optics - Focal length question

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