PHY 1371Dr. Jie Zou1 Chapter 36 Image Formation (Cont.)

PHY 1371Dr. Jie Zou2 Outline Images formed by refraction Spherical refracting surfaces Flat refracting surfaces Sign conventions for refracting surfaces

PHY 1371Dr. Jie Zou3 Images formed by refraction Consider only paraxial rays: Rays that diverge from the object and make a small angle with the principal axis. It can be shown that: Note: we must use the sign conventions when applying the above equation in different situations.

PHY 1371Dr. Jie Zou4 Sign conventions for refracting surfaces Front and back side of the refracting surface: The front side is the side of the surface in which light rays originate. The other side is the back side.

PHY 1371Dr. Jie Zou5 Flat refracting surfaces If a refracting surface is flat, then R , and we have: Note: the sign of q is opposite that of p. So, the image formed by a flat refracting surface is virtual and on the same side of the surface as the object. If n 1 >n 2, the image is formed between the object and the refracting surface. If n 1 <n 2, the image is formed to the left of the object.

PHY 1371Dr. Jie Zou6 Example 36.7 A set of coins is embedded in a spherical plastic paperweight having a radius of 3.0 cm. The index of refraction of the plastic is n 1 = One coin is located 2.0 cm from the edge of the sphere. Find the position of the image of the coin.

PHY 1371Dr. Jie Zou7 Example 36.8 A small fish is swimming at a depth d below the surface of a pond. What is the apparent depth of the fish?

PHY 1371Dr. Jie Zou8 Homework Ch. 36, P. 1170, Problems: #22, 25.