© 2010 pearson education, inc. slide 17-2 17 wave optics

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17 Wave Optics

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National Ignition Facility

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Power handling at the National Ignition Facility

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Chapter Six – Inductance and Capacitance

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Chapter Six – Inductance and Capacitance

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Chapter Six – Inductance and Capacitance

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Chapter Six – Inductance and Capacitance

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Index of Refraction

Slide 17-10

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Water Waves Spread Out behind a Small Opening

Slide 17-9

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Light Waves Also Spread Out Behind a Very Narrow Slit

Slide 17-11

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Reading Quiz1. All waves spread out after passing through a small enough

gap in a barrier. This phenomenon is known as

A. antireflection

B. double-slit interference

C. refraction

D. diffraction

Slide 17-5

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Answer 1. All waves spread out after passing through a small enough

gap in a barrier. This phenomenon is known as

A. antireflection

B. double-slit interference

C. refraction

D. diffraction

Slide 17-6

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Double-Slit Interference Experiment

Slide 17-12

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Analyzing the Double-Slit Experiment

Slide 17-13

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Bright and Dark Fringes in the Double-Slit Experiment

Slide 17-14

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The Diffraction Grating

Slide 17-16

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Bright Fringes for a Diffraction Grating

Slide 17-17

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The Intensity Pattern Due to a Diffraction Grating

Slide 17-18

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The Fringes Become Very Narrow as the Number of Slits is Increased

Slide 17-19

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A Diffraction Grating Splits Light into the Wavelengths That Make It Up

Slide 17-20

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Thin-Film Interference

Slide 17-21

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Phase Changes Due to Reflection

Slide 17-22

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Analyzing Thin-Film Interference

Slide 17-23

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Reading Quiz2. The wave model of light is needed to explain many of the

phenomena discussed in this chapter. Which of the following can be understood without appealing to the wave model?

A. single-slit diffraction

B. thin-film interference

C. sharp-ended shadows

D. double-slit interference

Slide 17-7

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Answer 2. The wave model of light is needed to explain many of the

phenomena discussed in this chapter. Which of the following can be understood without appealing to the wave model?

A. single-slit diffraction

B. thin-film interference

C. sharp-ended shadows

D. double-slit interference

Slide 17-8

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Single-Slit DiffractionLight passing through a narrow slit spreads out beyond the slit.

Slide 17-27

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Analyzing Single-Slit Diffraction

Slide 17-28

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Single-Slit Diffraction: Positions and Intensities

Slide 17-29

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Circular-Aperture Diffraction

Slide 17-30

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Summary

Slide 17-36

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Example ProblemTwo narrow slits 0.04 mm apart are illuminated by light from a HeNe laser (λ = 633 nm).

A. What is the angle of the first (m = 1) bright fringe?

B. What is the angle of the thirtieth bright fringe?

Slide 17-15

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Checking UnderstandingThe fringe pattern below could be due to

A. a single slit or two slits.

B. ten slits.

C. either two slits or ten slits.

D. either one slit or two slits.

Slide 17-31

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Answer The fringe pattern below could be due to

A. a single slit or two slits.

B. ten slits.

C. either two slits or ten slits.

D. either one slit or two slits.

Slide 17-32

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Huygens’ Principle Each point on a wavefront is a source of a secondary “wavelet” that continues the propagation. The combined wavelets form the new

wavefront.

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Two cases: A plane wave (or a linear wave if on a surface) and a spherical wave (or circular wave if

on a surface)

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Although only a few sources for

wavelets are shown, there are

an infinite number of them along the

wavefront

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Huygens’ Principle applied

to refraction of light.

V1 > V2 because the refractive

index of medium 2 is greater than

that of medium 1

The distance traveled over

time t is therefore different, V1*t >

V2*t

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The result is a change in direction or the wave. For light waves, this is represented by Snell’s law,

n1 * sin(theta1) = n2 * sin(theta2)

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Huygens University Marching Band Encounters Mud

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Huygens’ Principle applied to two slit

interference

Most of the wavelets are intercepted by the

barrier

Only the wavelets that are allowed through by the slits continue and combine to form the new set of waves

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Huygens and single slit diffraction

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Huygens Model of Reflection