Slide 1

Announcements Homework for tomorrow (Ch. 23, Probs. 11, 12, 15, & 48) 22.20: 2.9 22.30: a) double-slit as y is the sameb) 1.5 x 10 -4 m 22.31: a) single-slit b) 1.5 x 10 -4 m Office hours MW 12:30-1:30 pm TR 9-10 am F 1-2 pm Tutorial Learning Center (TLC) hours: MW 8-10 am, 12-6 pmR 8-12 pm, 2-6 pm T 8-1 pm, 2-6 pmF 8-10 am, 2-5 pm

Slide 2

Chapter 23 Ray Optics (Refraction)

Slide 3

The Law of Reflection is Snells Law is Last time

Slide 4

A laser beam is aimed at a 1.0 cm thick sheet of glass at an angle 30 above the glass. a. What is the laser beams direction of travel in the glass? b. What is its direction in the air on the other side? c. By what distance is the laser beam displaced? i.e. 23.3: Deflecting a laser beam

Slide 5

The figure below shows a laser beam deflected by a 30-60-90 prism. What is the prisms index of refraction? i.e. 23.4: Measuring the index of refraction

Slide 6

When a ray is transmitted into a material with a lower index of refraction, it bends away from the normal. There exists a critical angle, c, where one gets zero refraction! What is c ? Total Internal Reflection

Slide 7

When a ray is transmitted into a material with a lower index of refraction, it bends away from the normal. There exists a critical angle, c, where one gets zero refraction! What is c ? Notice: As 1 increases 2 approaches 90. fraction of transmitted light energy decreases. fraction of reflected light energy increases. Total Internal Reflection

Slide 8

A laser beam undergoes two refractions plus total internal reflection at the interface between medium 2 and medium 3. Which is true? 1. n 1 < n 3. 2. n 1 > n 3. 3. Theres not enough information to compare n 1 and n 3. Quiz Question 1

Slide 9

A light bulb is set in the bottom of a 3.0 m deep swimming pool. What is the diameter of the circle of light seen on the waters surface from above? i.e. 23.5: Total internal reflection

Slide 10

The most important modern application of total internal reflection (T.I.R.) is optical fibers. Light rays enter the glass fiber, then impinge on the inside wall of the glass at an angle above the critical angle, so they undergo T.I.R. and remain inside the glass. The light continues to bounce its way down the tube as if it were inside a pipe. Fiber Optics

Slide 11

In a practical optical fiber, a small-diameter glass core is surrounded by a layer of glass cladding. The glass used for the core and the cladding have: n core n cladding Fiber Optics