Waves

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Gives a brief description about light and sound waves a sound and comprehensive leading to the right presentation for schooling purposes.

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Waves

  1. 1. Waves
  2. 2. What are waves????? • A wave is a disturbance or oscillation that travels through space and matter, accompanied by a transfer of energy
  3. 3. Basic Terms… • Wavelength, λ • Amplitude • Speed, c • Frequency, f • Crest and trough for transverse waves, • Compression and rarefaction for longitudinal waves.
  4. 4. Types Of Waves
  5. 5. Difference Between…. •Longitudinal • Motion of the medium is parallel to the motion of the wave. • Example; Sound waves • Transverse • Motion of the medium is perpendicular to the motion of the wave. • Example ; waves in a ripple tank
  6. 6. Electromagnetic waves…… • Radiation consisting of waves of energy associated with electric and magnetic fields.
  7. 7. Properties of E.M.W’s • Travel with a constant velocity of 3 x 108 ms-1 in vacuum. • Not deflected by electric or magnetic field. • Show interference or diffraction. • Are transverse waves. • May be polarized. • Need no medium of propagation. The energy from the sun is received by the earth through electromagnetic waves.
  8. 8. Types of Electromagnetic Waves Electromagnetic waves Gamma rays X-rays Ultraviolet Radiation Visible Light Infrared Radiation Microwaves Radiowaves Increasing wavelength Increasing frequency
  9. 9. Uses Of Electromagnetic Waves.
  10. 10. Sound Waves…… • A wave of compression and rarefaction, by which sound is propagated in an elastic medium such as air.
  11. 11. Speed of Sound…. Material Speed of sound (m/s) Vacuum Does not travel Air 330 Water 1500 Metal 5000
  12. 12. Hearing sound… • Humans can hear sounds from 20Hz to 20 kHz. • Sound lower than 20Hz is known as infrasound while sounds higher than 20kHz are known as ultrasound.
  13. 13. Pitch, Loudness,…… • Loudness depends upon amplitude the greater the amplitude the louder the sound • Pitch is dependent upon the frequency ,higher the frequency higher the pitch and vice versa.
  14. 14. Ultrasound and Echo and its uses • Echo is the bouncing back of sound waves from a hard surface e.g. walls. • Ultrasound is the sound above 20kHz and is used in prenatal scanninng as well as in checking industrial materials.

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