24-1 Waves Versus Particles Huygens’ Principle and Diffraction
24-3 Interference – Young’s Double –Slit Experiment
23-4 The Visible Spectrum and Dispersion
23-5 Diffraction by a Single Slit or Disk
Objectives:
1. Explain Huygens’ Principle in terms of wave fronts.
2. How is Huygens’ Principle related to wave diffraction?
3. Explain if light can be diffracted.
4. What is the significance of Young’s Double Slit Experiment?
5. Explain how the destructive and destructive interference occurs in Young’s
Double Slit Experiment.
6. Explain the two important properties of light in relation to the wave theory of
light.
7. How is dispersion helpful in describing the energy of visible light?
8. Compare and contrast double slit and single slit diffraction.
Homework Problems: 2-10 even, 14, 15, 17-25 odd.
Vocabulary to Know For These Sections:
Electromagnetic wave
Huygens’ Principle
Wave front
Isotropic
Wavelets
Diffraction
Wave interference
Monochromatic
Constructive interference
Destructive interference
Wavelength
Amplitudes
Bright fringe
Dark fringe
Order
Maxima
Minimum
Frequency
Coherent sources
Incoherent sources
Intensity
Color
Visible Spectrum
Ultraviolet
Infrared
Dispersion
Index of refraction
Internal reflection
Diffraction pattern
Plane waves
Formula Search For These Sections: (identify the variable and its units)
Waves Versus Particles; Huygens’ Principle and Diffraction
1. What was the catalyst to the development of Huygens’ Principle?
2. State Huygens’ Principle.
3. What is an isotropic medium?
4. How is Huygens’ Principle useful for analyzing waves?
5. Compare and contrast the wave and ray model of light.
Interference – Young’s Double-Slit Experiment
1. How did the two slits actually produce light on a screen, and how did this differ
from the common theory of the day?
2. How did Young use wave interference to describe the series of bright lines?
3. How are the bright and dark fringes produced?
4. What happens to the bright fringes as they extend from the center?
5. How did Young determine the wavelengths of visible light?
6. Compare and contrast coherent and incoherent light sources.
The Visible Spectrum and Dispersion
1. Describe the two most obvious properties of light.
2. What are the extreme boundaries of the visible light spectrum?
3. Describe the dispersion of white light through a prism.
4. Explain how a rainbow is formed.
5. How does a diamond achieve its brilliance?
Diffraction By a Single Slit or Disk
1. What is Fresnel’s wave theory?
2. What is the “unexpected diffraction spot?”
3. How do the waves of light behave as they pass through different parts of the slit?
4. What is the pattern of light cancellation?
5. Compare and contrast the maxima and minima fringes for double and single slit
diffraction.
6. Describe the diffraction of light through a rectangular hole that is narrower in the
vertical direction than the horizontal.