WAVES

WAVES

1. REFLECTION

   • Bouncing back of a wave when it hits a surface and is unabsorbed

2. REFRACTION

   • Change of direction of a wave when it crosses a boundary where its speed changes

3. DIFFRACTION

   • Spreading of waves on passing through a gap which is the same order of magnitude as its wavelength

4. POLARISATION

   • Longitudinal waves cannot be polarised as the oscillations of particles run ONLY parallel to the direction of wave travel.
   • Transverse waves can be polarised as the oscillations of particles are perpendicular at different orientations around the wave.
   • In unpolarised transverse waves, the vibrations of the particles can change from one plane to another. In plane-polarised transverse waves, the vibrations of the particles remain in one plane.

5. TRANSVERSE

   • The oscillations of particles are perpendicular to the direction of wave travel
   • Electromagnetic waves are an example of transverse waves
     • Uses of EM waves include: communications sterilisation illumination
       • Radio waves are used for commuunicatoons
       • Gamma waves are used for sterilisation
       • Infrared waves and microwaves are used in cooking
       • Visible light waves are used by plants and animals
         • Plants use visible light waves for photosynthesis
         • Humans use visible light in order to see!
       • Gamma rays are used for the detection and treatment of cancer
       • X-rays are used in airport security scanners

6. LONGITUDINAL

   • The oscillations of the particles are parallel to the direction of wave travel
   • Sound waves are an example of longitudinal waves

7. The phase of a vibrating particle at a given time is the fraction of a cycle it has completed since the beginning of a cycle

8. The number of waves passing a certain point each second is called the frequency

9. v = f x λ

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