Science & Technology in Action

16th Edition

Electromagnetic radiation & 5G – myths and facts


Politics & Society
Fifth Generation (5G) services allow higher data rates – possibly ten times that of 4G but not all phones are capable of using it. In Ireland 5G will be provided on 700 MHz, 3.6 GHz and 26 GHz bands. The different ‘generations’ of phone technology all use parts of the radio spectrum whose energy is much lower than that of visible light.

Available downloads

The full lessons along with a supporting toolkit are available in three different formats, A4, A3 and as a Powerpoint deck.

Lesson excerpt

What is 5G?

The term 5G refers to the fifth generation of wireless technology which is currently being introduced in some cities and areas of higher population density in Ireland. First generation devices, 1G, were limited to calls while the second, 2G, added text messaging or SMS (short message service). The third generation, 3G, allowed access to the internet and the current 4G allows faster data transfer with smoother internet browsing and video. 5G is the coming generation, and is forecast to have a revolutionary impact on business and society in general.

The underlying technology

All five generations of wireless technologies, and indeed all radio, TV and satellite communications, use frequencies in the radio and microwave sections of the electromagnetic spectrum. The electromagnetic spectrum also includes visible light, infrared (i.e. heat radiation), ultraviolet and X-rays. What distinguishes them is their frequency and hence their wavelength; the higher the frequency, the shorter the wavelength. The diagram shows where they are located in the spectrum.

Some background

In 1665 the great British scientist Robert Hooke proposed that light was some kind of wave. In 1690 the Dutch mathematician-astronomer Christiaan Huygens proposed the first detailed wave theory of light. In 1675 and again in 1725 Isaac Newton proposed that light was composed of particles that had mass which varied with the colour. He explained the properties of light in terms of gravitation. Because of his reputation no one challenged his theory. However, around 1800 Thomas Young showed conclusively that light behaves as a wave. But no one knew what was actually ‘waving’. The particle theory was abandoned – for the moment. Around the same year invisible rays were discovered at either side of the visible spectrum; these were called infrared (i.e. below red; IR) and ultra violet (i.e. beyond violet; UV).

True or False?

  1. Each generation of mobile phones was faster than the previous one. true
  2. Mobile phone signals are sound waves. false
  3. Higher frequency waves have shorter wavelengths. true
  4. Huygens devised the electromagnetic theory of light. false
  5. The energy of photons is proportional to their wavelength. false
  6. All electromagnetic radiation is non-ionising. false
  7. The energy of ionising radiation is usually expressed in electron-volts (eV). true
  8. 26 GHz radio waves have longer wavelength and lower energy than visible light. true
  9. Only a small fraction of the electromagnetic radiation we receive is man-made; most of it is natural. true
  10. Blackbody radiation refers to the electromagnetic radiation emitted by everything in the universe. true
  11. 26 GHz radio waves are easily absorbed by walls etc. true