Applications of Convex and Concave Lens

In this activity, you will revisit the two videos about how light is refracted when incident on a lens. First, open the convex lens video. Observe how the light rays parallel to the principal axis behave when they hit the convex lens at different points. You can replay the video any time during this activity.

convex lens: https://www.rit.edu/cos/livephoto/LPVideos/refl-refr/convex_lens.mp4

Then, watch the second concave lens video. Observe how the light rays parallel to the principal axis behave when they hit the lens at different points. You can replay the video any time during this activity.

concave lens: https://www.rit.edu/cos/livephoto/LPVideos/refl-refr/concave_lens.mp4

Part A

Describe what happens to the incoming parallel rays for the two lenses. Compare and contrast the results.

Part B

Below is a list of some applications of lenses. Determine which lens could be used in each and explain why it would work. You can conduct online research to help you in this activity, if you wish.

Applications	Lens Used	Reason
peephole in a door
objective lens (front lens) of binoculars
photodiode - In a garage door or burglar alarm, it can sense the light (or the lack of it) from an LED light source positioned some distance away.
magnifying glass
viewfinder of a simple camera