Download the App!

Get 24/7 study help with the Numerade app for iOS and Android! Enter your email for an invite.

$\bullet$$\bullet$ A laser beam shines along the surface of a block of transparent material. (See Figure $23.53 .)$ Half of the beam goes straight to a detector, while the other half travels through the block and then hits the detector. The time delay between the arrival of the two light beams at the detector is 6.25 ns. What is the index of refraction of this material?

Get the answer to your homework problem.

Try Numerade free for 7 days

Like

Report

$v=1.71 . m / s$$n=1.75 .10^{8}$

Physics 102 Electricity and Magnetism

Physics 103

Chapter 23

Electromagnetic Waves and Propagationof Light

Electromagnetic Waves

Reflection and Refraction of Light

Cornell University

University of Washington

Hope College

Lectures

02:30

In optics, ray optics is a geometric optics method that uses ray tracing to model the propagation of light through an optical system. As in all geometric optics methods, the ray optics model assumes that light travels in straight lines and that the index of refraction of the optical material remains constant throughout the system.

10:00

In optics, reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The law of reflection says that for specular reflection the angle at which the wave is incident on the surface equals the angle at which it is reflected. Reflection may also be referred to as "mirror image" or "specular reflection". Refraction is the change in direction of a wave due to a change in its speed. The refractive index of a material is a measure of its ability to change the direction of a wave. A material with a higher refractive index will change the direction of a wave to a greater degree than a material with a lower refractive index. When a wave crosses the boundary between two materials with different refractive indices, part of the wave is refracted; that is, it changes direction. The ratio of the speeds of propagation of the two waves determines the angle of refraction, which is the angle between the direction of the incident and the refractive rays.

04:12

A laser beam shines along …

0:00

04:18

04:34

ages 33.8 laser beam Figur…

01:20

$\bullet$$\bullet$ Using a…

01:47

Using a fast-pulsed laser …

02:37

Using a block of a transpa…

04:44

A laser beam is traveling …

03:35

A thin sheet of transparen…

first, let's figure out the time it takes for the part traveling an heir to recent in sector and so the time is just going to be equal to the distance over the speed. But the part moving in the air is going to be moving at the speed of light. And so the distance is 2.5 meters in the speed of light is 3.0 times 10 to the eight meters per second. And so this equals 8.33 times 10 to the minus nine seconds. This is just for the airport. So now the block part, we're told has some delay and so it's going to take a little bit longer than this. And so we'll start out with this amount and we know that it's delayed by 6.25 nanoseconds or times tends the nice nine seconds. And so this amount, plus the delay, is the toll time in the block. And so this is 1.46 times 10 98 seconds. Now we know the time it takes in the block. We can figure out what the speed and the block ISS, and we could do that using this. Flossie is distance over time. The distance is the exact same as before. It's 2.5 meters. In the time we just found this one point for six times 10 to the minus eight seconds. And so the speed is 1.71 times 10 to the eighth meters per second. Now that we know the speed that it's moving in the block, we can figure out the index of refraction of block by taking the ratio of the speeds. And so the speed of light is just three times 10 to the eighth. In this philosophy and block, we just found 1.71 times 10 to the eighth. That's in meters per second, and so is this. So the unit's cancel and for the index, I get one point 75 and that's the answer.

View More Answers From This Book

Find Another Textbook

Numerade Educator