Pre-class Exercise #13

Add/Remove:    Far Source     Near Source     Eye Glasses


The above applet models the eye.  The slider can be used to simulate the eye's ability to accommodate.  The location of the near source can be changed by dragging the source.  The focal length of the eyeglass can be altered by clicking on the eyeglass and then dragging one of the vertical white markers.  Drag a marker through the lens in order to change between converging and diverging lenses.



  1. Describe the eye represented above.

 A.  Normal.

 B.  Nearsighted.

 C. Farsighted.



2. If the eye is nearsighted, what focal length eyeglasses should be used for normal vision (can see far away objects with eyes relaxed, and also focus on an object at x=2.0).  If the eye is farsighted, what focal length eyeglasses should be used to allow the person to see an object at x=2.0?

  A.  No glasses needed.

  B. +0.8 (arbitrary units)

  C. +5.7 (arbitrary units)

  D. -4.6 (arbitrary units)



This Physlet was created by Melissa Dancy and Wolfgang Christian.