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Oscillations and Waves Wave Characteristics

Oscillations and Waves Wave Characteristics. 4.4 Wave characteristics 4.4.1 Describe a wave pulse and a continuous progressive (travelling) wave. 4.4.2 State that progressive (travelling) waves transfer energy. 4.4.3 Describe and give examples of transverse and of longitudinal waves.

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Oscillations and Waves Wave Characteristics

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  1. Oscillations and WavesWave Characteristics

  2. 4.4 Wave characteristics 4.4.1 Describe a wave pulse and a continuous progressive (travelling) wave. 4.4.2 State that progressive (travelling) waves transfer energy. 4.4.3 Describe and give examples of transverse and of longitudinal waves. 4.4.4 Describe waves in two dimensions, including the concepts of wavefronts and of rays. 4.4.5 Describe the terms crest, trough, compression and rarefaction. 4.4.6 Define the terms displacement, amplitude, frequency, period, wavelength, wave speed and intensity. 4.4.7 Draw and explain displacement–time graphs and displacement–position graphs for transverse and for longitudinal waves. 4.4.8 Derive and apply the relationship between wave speed, wavelength and frequency. 4.4.9 State that all electromagnetic waves travel with the same speed in free space, and recall the orders of magnitude of the wavelengths of the principal radiations in the electromagnetic spectrum.

  3. All WAVES involve the transfer of energy without a net transfer of matter. You can see this happen when you play with slinkies …

  4. There are two types of waves, Longitudinal and Transverse. Longitudinal waves involve particles of the medium vibrating parallel to thedirection of travel of the energy. http://www.schulphysik.de/suren/Applets.html

  5. Transverse waves are created when the direction of the vibration of theparticle of the medium is 90° (perpendicular) to the direction of travel of the wave energy itself. http://www.schulphysik.de/suren/Applets.html

  6. To represent waves we often use graphs. There are two types. Displacement – time graphs and Displacement – distance graphs. The “displacement” refers to how far a particle has been displaced by the wave’s energy.This can happen in a longitudinal or transverse direction. The Period, T, of a wave is the time it takes to complete one cycle. It’s measured in seconds, s.

  7. The Wavelength, , is the distance between troughs or crests of a wave. It’s measured in metres, m. The Amplitude, A, of a wave is the value of the maximum displacement ofa particle from its mean position. It is also measured in metres, m.

  8. The Frequency, f,of a waveis the number of vibrationsor cycles that are completed per second. It is measured in Hertz, Hz. It is related to the period by the following equation.

  9. The frequency, wavelength and speed of a wave are linked by the Wave Equation:

  10. Each bright line in this diagram represents a crest and can be regarded as a WAVEFRONT.

  11. A RAY can be thought of as a locus of one point on a wavefront showing the direction in which energy is travelling.

  12. Download from http://phet.colorado.edu/simulations/index.php?cat=Sound_and_Waves

  13. In the late 19th century physicists had been working extensively with electricity and magnetic fields. A great many discoveries in these fields were being made. At the same time it became universally accepted that the best model for light was the wave model. James Clerk Maxwell summarised, synthesised and unified these ideas. He came up with the idea that all of these phenomena, including light, were simply different forms of ELECTROMAGNETIC RADIATION

  14. Electromagnetic waves are created by accelerating charges which result in a rapidly changing magnetic field and electric field travelling at right angles to each other and to their direction of travel. EM Wave applet: http://micro.magnet.fsu.edu/primer/java/scienceopticsu/electromagnetic/index.html

  15. Although the previous image showed only two transverse waves, EM waves don’t look like these in reality. There are actually many planes of electric-magnetic field oscillations. Source: http://sol.sci.uop.edu/~jfalward/physics17/chapter11/chapter11.html

  16. It is the FREQUENCY of the waves that determines the type of electromagnetic wave and the different frequencies make up the ELECTROMAGNETIC SPECTRUM Source: http://outreach.atnf.csiro.au/education/senior/astrophysics/images/em_spectrumextended.jpg

  17. Note that VISIBLE LIGHT only makes up a small part of the spectrum Source: http://imgs.xkcd.com/comics/electromagnetic_spectrum_small.png

  18. All electromagnetic waves travel with the same speed in free space. It is worthwhile to recall the orders of magnitude of the wavelengths of the principal radiations in the electromagnetic spectrum, such as the following

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