Homework Assignment #5
Thin Lenses, Images and the Lensmakers Formula
What you will learn from this section
- Terminology and sign convention for solving thin lens
problems
- The names of different shape converging and diverging
lenses
- use of the lensmakers' formula to calculate focal length
- locating images by ray tracing
- optics vocabulary for this section:
- thin lens
- converging lens
- diverging lens
- real focal point
- virtual focal point
- Principle rays: focal, parallel, central
How to approach this material
- Read section 3, Geometric Optics, from pages 33- page 41. Pay
particular attention to the graphics.
CORRECTION TO
NOTES: On page 38, the paragraph
next to the sketch of the lens should read:
SOLUTION: The radius of curvature on the
left side is positive (+10 cm) because the curve opens to the right.
The radius of curvature on the right side is negative (-40 cm)
because the curve opens to the left. The larger radius of curvature
is on the right where the lens is flatter.
- Visit these web sites. Some show mirrors as well as lenses.
The first two define the three principle rays and the third allows
you to change thefocal length of a lens and see how the image
location and size change:
- Do the homework problems in this folder.
- The lab this week is on taking measurements.
If you have questions
- Send an email to Judy jdonnelly@trcc.commnet.edu or to Randy
rseebeck@trcc.commnet.edu
- Post a question in the discussion forum
- Talk with a mentor, or another student (we learn best when we
help each other!)
- Stop by the Virtual Classroom during posted office hours
When you are finished
- Fax (860 886-5063) or email your homework to me by the due
date. (see the assignment folder) If you fax, be sure to write
"ATTN: JUDY DONNELLY" on the first page, and to number the
pages.
- Check the calendar for the due date for the lab.