EM waves and the electromagnetic spectrum
A transverse wave caused by oscillations in an electromagnetic field. are transverse waves. Their vibrations or Vibration. are changes in electrical and magnetic fields at right angles to the direction of wave travel.
All electromagnetic waves:
- transfer energy as Energy transferred as a wave spreading out from a source - eg light, infrared, sound. from the source of the waves to an absorber
- can travel through a A volume that contains no matter. such as in space
- travel at the same speed through a vacuum or the air
Electromagnetic waves travel at 300,000,000 metres per second (m/s) through a vacuum.
Electromagnetic spectrum
Electromagnetic waves form a continuous A series of similar waves arranged in order of wavelength or frequency. of waves. This includes:
- waves with a very short The length of a single wave, measured from one wave peak to the next., high The number of waves produced each second. The unit of frequency is hertz (Hz). and high energy
- waves with a very long wavelength, low frequency and low energy
Electromagnetic waves can be separated into seven distinct groups in the spectrum.
Often a phrase is used to help remember the order of the groups of the electromagnetic spectrum such as Roman Men Invented Very Unusual X-ray Guns.
Each group contains a range of frequencies. For example, visible light contains the limited range of frequencies that can be detected by the human eye:
- red light has the lowest frequencies of visible light
- violet light has the highest frequencies of visible light