Copy of 1345+Overhead+Slides_Waves+and+Wave+Optics

Waves

• Overview of Topics

  • Wave pulses

  • Sinusoidal Waves

  • Interference and Diffraction

  • Wave model of light

Wave Pulses

Understanding Oscillations and Waves

• Oscillations:

  • Involve individual entities that vary periodically over time (e.g., back and forth)

  • Examples include:

    • Pendula

    • Molecular vibrations

    • Heartbeats

    • Firefly lights

    • Voltage in power grids

    • Some types of enzyme production

• Waves:

  • Collections of individual entities that vary together in time and space, which may or may not be periodic

  • Examples include:

    • Light

    • Sound

    • Water waves

    • Earthquakes

    • Electrochemical signals in neurons

Differences between Oscillations and Waves

• Oscillations operate on individual elements, whereas waves represent collective behavior among multiple elements.

A Moving Pulse

• Study a wave pulse and its motion

Sketching the Movement

• Diagram Requirements:

  • Show the y position of a bead as a function of time.

Further Illustration of Moving Pulses

• Visualize wave form changes over time by sketching the initial wave followed by its form at later intervals.

• Sketch Sequence:

  • Initial wave pulse

  • Wave pulse after a short duration

  • Wave pulse a bit later

Bead Movement in a Pulse

• Illustrate how individual beads in a pulse move from one position to another

• Position Changes:

  • Indicate the direction and extent of movement through vertical arrows from initial to new positions of the wave pulse.

Observations of Wave Pulses

• Snapshot Analysis:

  • Discuss how a point on the string shows its y-displacement, y-velocity, x-velocity, and y-force at different times visually represented by images.

Reflection at Wave Ends

• Fixed End:

  • Discuss behaviors of waves when encountering fixed ends (e.g., bounce back upside down).

• Loose End:

  • Discuss behaviors of waves when encountering loose ends.

Interference and Wave Combination

• Wave Interference:

  • Understand how two or more wave pulses interact, including condition where they overlap perfectly to reinforce.

The Big Picture of Waves

• Key Considerations:

  • Wave shape (f(x,t)), wave speed (v), and local medium speeds

  • Understand how wave shapes combine

  • Wave Relationships:

    • Wavelength (λ), frequency (f), and speed (v) correlate in sinusoidal waves

Controlling Wave Speed

• Examine factors influencing wave pulse speed:

  • Hand motion frequency and amplitude

  • String density and tension adjustments

Sinusoidal and Standing Waves

• Develop an understanding of the equations governing sinusoidal waves, including definitions for key parameters like k, λ, ω, f, and T

Calculating Wave Speed

• Connect graphical information to wave speed calculations in practice, specifically using oscillation tests.

Resonant Frequencies

• Discuss how resonant frequencies relate to wave patterns using small amplitudes.

Two-Slit Interference

• Understand how light behaves when traveling through slits, focusing on the differing results than predicted by standard ray models.

Characteristics of Light Waves

• Explore the wave spectrum of light, providing details on wavelength and frequency differences across the electromagnetic spectrum.

• Spectrum Chart:

  • Ranges from radio waves to gamma rays, detailing energy levels and wavelengths from visible light (400-700 nm) to high-energy UV rays.

Comparison of Color and Wavelength

• Examine how changes in wavelength affect interference patterns, considering how moving closer affects observed patterns.

Interaction of Photons

• Explain absorption and emission concepts in the light-matter interaction, emphasizing their resonance with specific energies.

Energy Quantization

• Discuss how energy levels in atoms are quantized and how this leads to photon interactions during absorption and emission.