SOLUTION: shown in the figure is a simple magnifier consisting of a convex lens. the object to be magnified is positioned so that its distance p from the lens than the focal length f. the li

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Question 921625: shown in the figure is a simple magnifier consisting of a convex lens. the object to be magnified is positioned so that its distance p from the lens than the focal length f. the linear magnification M is the ratio of the image size to the object size. it is shows in physics that M=f(f-p). if f=6 cm, how far should the object be placed from the lens so that its image appears at least three times as large?

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
You need to make M=3 with a lens that has f=6 .
Your formula is wrong. It should be M=f%2F%28f-p%29 .
That way with numerator (f) and denominator (f-p) in the same units, you get a ratio of lengths for M.
(I was once a high school physics teacher, and I also checked the formula to make sure my memory was not failing me after so many years of not teaching this stuff).
Regardless of the formula, all you had to do was plug in the given values for M and f, and then solving for p.
Plugging those values in you get

The object be placed at most highlight%284cm%29 from the lens for its image to appear at least three times as large.