Welcome to the Phy122 online optics learning module: "Refraction & Lenses"!
In this online learning tool, you can study how light rays refract, what Snell's law is and how to use it, how a convex lens produces a real or a virtual image, and how a concave lens produces a virtual image. You can also see applications of these principles demonstrated in the problems that are solved in the videos.
Let me explain briefly how you should work with this tutorial. The tutorial contains pages with graphics and narration explaining the physics. There are also interactive animations that allow you to do "virtual" experiments, and to explore these concepts in more detail. Please take your time playing with the interactive animations, and make sure you are observing carefully what happens.The questions posed throughout the tutorial are meant to guide you in your studies, and to help you identify the key points you have to understand.
One more remark: In this tutorial, you are using the ray model of light, which describes light rays as propagating in straight lines. This is in contrast to the wave model of light, which describes light as an electromagnetic wave. Certain optical phenomena, such as interference and diffraction, can only be understood within the framework of the wave model of light, and will therefore not be considered in this tutorial.