1 / 23

Waves

Waves. Vocabulary Review Properties of Waves The Electromagnetic Spectrum. Vocabulary Review. Progressive waves Describing wave motion Displacement Amplitude Wavelength Period Frequency Speed. Intensity. Energy passing through a unit area in unit time.

liv
Download Presentation

Waves

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Waves Vocabulary Review Properties of Waves The Electromagnetic Spectrum

  2. Vocabulary Review • Progressive waves • Describing wave motion • Displacement • Amplitude • Wavelength • Period • Frequency • Speed

  3. Intensity • Energy passing through a unit area in unit time. • Intensity ~ Square of the amplitude • I ~ A2 • Intensity ~ 1/d2 • Where d is distance from source

  4. Example 1 • A health inspector is measuring the intensity of a sound. Near a loudspeaker his meter records an intensity I. This corresponds to an amplitude A of the sound wave. At another position the meter gives an intensity reading of 2 I. What is the corresponding sound wave amplitude?

  5. Example 2 • The intensity I of a sound at a point P is inversely proportional to the square of the distance x of P from the source of the sound.Air molecules at P, a distance r from S, oscillate with amplitude 8.0 μm. Point Q is situated a distance 2r from S. What is the amplitude of oscillation of air molecules at Q?

  6. Phase • The angle at which the wave motion started.

  7. Phase 0⁰ 180⁰ or п

  8. Phase 90⁰ or п/2 270⁰ or 3п/2

  9. Phase Difference • The difference in angles between two waves at a specific point.

  10. Phase Difference Phase difference of п at all points

  11. Phase Difference Phase difference of п at all points

  12. Coherence When two waves have constant phase difference, then they are coherent. Coherence occurs when two waves have the same frequency or period.

  13. Non-Coherence

  14. In Phase Phase difference is a multiple of 2п at all points.

  15. Out of Phase Phase difference is not a multiple of 2п.

  16. Out of Phase Phase difference of п at all points

  17. Wave Properties • For all waves • Reflection • Bouncing of waves off a surface • Refraction • Change of wave speed as it passes from one medium to another (from one depth to another) • Bending of waves • Diffraction • Bending of waves around a barrier

  18. Wave Properties Question • Which wave properties change when light passes from air into glass? • A colour and speed • B frequency and wavelength • C speed and wavelength • D wavelength and colour

  19. Polarisation • Oscillation that takes place in one direction. • Only true for transverse waves.

  20. Polarisation

  21. The Electromagnetic Spectrum • Electromagnetic waves are transverse waves • They are non-mechanical waves • Do not require a medium to transfer energy • Travel at the same speed in a vacuum • 3 x 10 8 ms-1

  22. Orders of Magnitude (Wavelength) • Gamma Rays • X-Rays • Ultraviolet Rays • Visible Light • ROY G BIV • 10 -14 m • 10-10 m • 10-7 m • 10-7m • (700 nm -400 nm)

  23. Orders of Magnitude (Wavelength) • Infrared • Microwaves • Radio Waves • 10 -6 m • 10-2 m • 10 2 m

More Related