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

A 2.0-cm-diameter spider is 1.80 m from a wall.

A. Determine the focal length of a lens that will make a half-size image of the spider on the wall.

B. Determine the position (measured from the wall) of a lens that will make a half-size image of the spider on the wall.

2. Relevant equations

(1/p) + (1/q) = (1/f)

m = (-q/p)

3. The attempt at a solution

I couldn't figure out where to start. I understand that the magnification should be (-.05) but then I can't use that equation because I don't know the original focal length. Would 1.80 m be the image distance? I wish the problem would have provided more information!

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# Homework Help: Lens and Focal Length

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