Geometric Optics

Converging Lenses

Seat Experiment
Use a converging lens and a file card to help describe images. Sketch crude ray diagrams and use standard image characteristics (real vs. virtual, erect vs. inverted, enlarged vs. reduced.)

Q1: Describe how a distant object appears through a converging lens.

Q2: Look at closer objects and very close objects, describe the images. Are there any differences?

Q3: What are the differences between converging lenses and spherical mirrors?

Use a converging lens to produce a spot of light on a 3" x 5" card. Focus all the light at a single spot.

Q4: Experimentally calculate the focal length of the lens.

Project an image, such as a spray bottle of Windex as viewed in this picture, onto a 3" x 5" card using a converging lens.

Q5: Characterize the image that was produced on the 3" x 5" and sketch the ray diagram.

Q6: State rough estimate values for hi, ho, M, di, and do.

Q7: Using the thin lens equation mathematically calculate the focal length of your lens.



Teaching Notes