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WAVES ( General waves properties)

WAVES ( General waves properties) . Q. What is a wave? It is a periodic disturbance which allows the transfer of energy (by means of vibration ) from one point to another without the physical transfer of the medium (such as water wave). WAVE. Stationary waves

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WAVES ( General waves properties)

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  1. WAVES ( General waves properties) Q. What is a wave? It is a periodic disturbance which allows the transfer of energy (by means of vibration ) from one point to another without the physical transfer of the medium (such as waterwave)

  2. WAVE Stationary waves - vibration about an equilibrium position only e.gstring waves. Progressive waves - propagate energy e.g water waves, sound and Sound waves.

  3. Progressive waves Transverse waves -vibration are perpendicular to the direction of propagation e.g water waves, light waves. Longitudinal waves - vibration are parallel to the direction of propagation e.g sound wave.

  4. Transverse waves (e.g: light waves, water waves) 1. The vibration are parallel to the direction of propagation. 2. Transverse Waves are progressive (propagate energy )

  5. λ • 3. (i) water profile • displacement C C λ a λ distance a λ T T

  6. (ii) Crest, C, is the highest position in the wave. • (iii) through, T, is the lowest position in the wave. • (iv) amplitude, a, largest (maximum ) displacement from the equilibrium position. • (v)Wave length, , is the distance between two consecution crests or troughs. • orThe wave length, , is the distance between 2 consecutive homologuousmolecules moving in the same direction. The wave length, , is the distance of one cycle. • (vi) The frequency, f, of a wave is the number of complete cycle which cross a fixed point per second. • It is measured in cycles per second or Hertz (HZ). • (vii) The velocity of propagation, V, is the distance travelled by the wave in the direction of propagation per second. V = f 

  7. (viii) Wave front • 1. Wavefrontis any line or section taken through an advancing wave in which all the particles are moving in the same phase • (same phase = same direction) Wavefronts are positions of crests as soon from above rope )between the two points λ PARALLEL WAVEFRONTS λ Extended source C C C C C

  8. Production of plane wavefront in ripple tank by using a : • vibrating bar • straight edge • or vibrating ruler Production of circular wavefront by using a dipper.   • All transverse waves may : • reflect • refract • diffract • interfere • polarize

  9. Reflection of plane wavefront by a plane barrier Plane barrier λ Incident wavefront λ Reflected wavefront

  10. Reflection pf plane wavefront by an inclined plane barrier

  11. NOTE: During reflection: • the wavelength, is constant • the frequency is constant • velocity changes (direction) • speed does not change

  12. (ii)Refraction • Refraction is a change in direction of the wave due to a change in velocity • (i) Refraction of light waves : the change in velocity is caused by a change in density of medium i.e when light passes from a less dense medium into a denser medium (or vice versa), refraction takes place

  13. Refraction of water waves • The change in velocity is caused by a change in depth. Water waves have high velocities in deep water and small velocities in shallow water.

  14. V1 V2 λ λ Shallow water Deep water

  15. Normal shallow deep

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