Farsightedness

Blackboard optics is used to demonstrate how the effective focal length of a lens can be changed by adding another lens to it. Then on the lecture table, the image of a light bulb is projected through a converging lens onto a nearby screen to show sharp focus for a farsighted eye. Next, the light bulb is moved closer to the lens to blur the image and simulate farsightedness. A second converging lens is placed in front of the first lens which brings the image again into focus, thereby correcting the farsightedness. Equipment: - Blackboard optics equipment - Two converging lenses - Light source - Small screen - Stands for lenses and screen ---------------------------- This video is part of the project "Videos of Physics Demonstrations", which is created by Dr. Galli and Dr. Amiri of Physics Department, Weber State University. To access the full library of the videos, please visit this link: https://www.weber.edu/physics/amiri_galli.html Links to University and Department: Weber State University Homepage: https://www.weber.edu/ WSU Physics Department: https://www.weber.edu/physics