Physics 109 1st Edition Lecture 3 Outline of Last Lecture I Refraction of Light a Snell s law II Total Internal Reflection III Refraction Examples Outline of Current Lecture I The prism II Converging lens a 3 easy rays b lens formula c magnification d finding image size Current Lecture I The Prism a When surfaces of block glass or plexiglass are not parallel as in a prism the incoming and outgoing rays of light are not parallel i When light travels through a prism the end result is always that the ray is deflected away from the apex of the prism These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II Converging Lens a Converging lens are thicker in the middle than near the edges so they deflect light toward an axis b Focal point the point at which the rays converge at a certain distance from the lens c 3 easy rays for when the object length focal length i A ray from the object through the center of the thin lens This ray goes straight through because at the center of the lens the two lens faces are parallel to each other ii A ray from the object to the lens parallel to the optical axis This ray goes through the focal point on the other side of the lens iii A ray from the object through the focal point on the same side of the lens as the object This ray will leave the lens traveling parallel to the axis d Lens Formula 1 o 1 i 1 f o lens to object i lens to image f lens to focal point e Magnification M i o i The bigger the object is the smaller the image is ii The smaller the object is the bigger the image is f How to find the image size i o height of the object g The image for o f is real and upside down h When f o the image is virtual and upright and the rays are different see image on next page