Thin Lens And Lens Maker Equations Video Lessons

Concept

# Problem: A 2.0-cm-diameter spider is 2.0 m from a wall.Determine the focal length and position (measured from the wall) of a lens that will make a half-size image of the spider on the wall.

###### FREE Expert Solution

Lens equation:
$\overline{)\frac{\mathbf{1}}{{\mathbit{s}}_{\mathbit{o}}}{\mathbf{+}}\frac{\mathbf{1}}{{\mathbit{s}}_{\mathbit{i}}}{\mathbf{=}}\frac{\mathbf{1}}{\mathbit{f}}}$

Magnification:

$\overline{){\mathbf{m}}{\mathbf{=}}\frac{{\mathbf{h}}_{\mathbf{i}}}{{\mathbf{h}}_{\mathbf{o}}}{\mathbf{=}}{\mathbf{-}}\frac{{\mathbf{s}}_{\mathbf{i}}}{{\mathbf{s}}_{\mathbf{o}}}}$

The distance between the object and the image is:

so + si = 2.0 m

Magnification, m = -si/so = 1/2

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###### Problem Details

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

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