Electromagnetic spectrum
Core concepts and learning points for this section:
Syllabus Points
Core
Supplement
- 3.3.3 Know that the speed of electromagnetic 8 waves in a vacuum is 3.0 × 10 m / s and is approximately the same in air continued www.cambridgeinternational.org/igcse 25 Subject content
- 3.3.4 Know that many important systems of communications rely on electromagnetic radiation including: (a) mobile phones (cell phones) and wireless internet use microwaves because microwaves can penetrate some walls and only require a short aerial for transmission and reception (b) Bluetooth uses radio waves because radio waves pass through walls but the signal is weakened on doing so (c) optical fibres (visible light or infrared) are used for cable television and high-speed broadband because glass is transparent to visible light and some infrared; visible light and short wavelength infrared can carry high rates of data
- 3.3.5 Know the difference between a digital and analogue signal
- 3.3.6 Know that a sound can be transmitted as a digital or analogue signal
- 3.3.7 Explain the benefits of digital signalling including increased rate of transmission of data and increased range due to accurate signal regeneration
- 3.3.8 Know the difference between a digital and analogue signal
- 3.3.9 Know that a sound can be transmitted as a digital or analogue signal
- 3.3.10 Explain the benefits of digital signalling including increased rate of transmission of data and increased range due to accurate signal regeneration