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3 Cards in this Set
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Waves transfer energy and information without transferring matter. |
Waves can be described by their:
Frequency - the number of waves passing a point each second, measured in hertz (Hz) Speed - measuring in metres per second (m/s) Wavelength and Amplitude |
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Longitudinal Waves Sound waves and seismic P waves are longitudinal waves. The particles in the material, the sound is the travelling through move back and forth along the same direction that the sound is travelling.
Particles in a longitudinal wave move along the same direction as the wave. |
Transverse Waves Waves on a water surface, electromagnetic waves and seismic S waves are all transverse waves. The particles of water move in a direction at right angles to the direction the wave is travelling. |
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Ionising Radiation All electromagnetic waves transfer energy. The amount of energy transferred depends on the frequency of the wave. The higher the frequency, the more energy the wave transfers.
higher frequency = more energy = more harmful |
Radioactive Sources Some elements are radioactive. These elements naturally emit ionising radiation all the time. The ionising radiation can be alpha, particles, beta particles or gamma rays. All forms of ionising radiation transfer energy.
Effects of ionisation The energy transferred by ionising radiation can remove electrons from atoms to form ions. Ions are very reactive and can cause mutations to the DNA in cells. This can lead to cancer. Too much ionising radiation can kill cells, which is why gamma rays are useful for sterilising surgical instruments. |
