1. Today’s agenda: Death Rays. You must know when to run from Death Rays. Refraction at Spherical Surfaces. You must be able to calculate properties of images formed by refraction at spherical surfaces. Thin Lenses: Concave and Convex Lenses, Ray Diagrams, Solving the Lens Equation. You must understand the differences between these two kinds of lenses, be able to draw ray diagrams for both kinds of lenses, and be able to solve the lens equation for both kinds of lenses. Lens Combinations, Optical Instruments. You should be aware of this useful information, which will not be presented in lecture.

2. Lens Combinations To determine the image formed by a combination of two lenses, simply... …calculate the image formed by the first lens… …then use the first lens image as the source (object) for the second lens. There is no homework on lens combinations.

3. Optical Instruments A Simple Magnifier h  O h ´´ Magnifier F I q p  25 cm (near point) O

4. Refracting Telescope For viewing very far objects. Object distance taken as infinity.

5. Terrestrial Telescopes For producing upright images: Galilean telescope Field-lens telescope

6. Reflecting Telescope Newtonian-focus reflecting telescope

7. Compound Microscope Again has objective and eyepiece, but because it is for viewing very near objects it is very different from the telescope. Eyepiece magnification: Objective magnification: Overall magnification: