Cambridge IGCSE Physics

3.3Electromagnetic spectrum

Electromagnetic spectrum in Cambridge IGCSE Physics: what the syllabus expects you to know, the learning objectives and how to practise.

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Learning objectives

What the syllabus expects you to be able to do.

3.3.1Know the main regions of the electromagnetic spectrum in order of frequency and of wavelength.
3.3.2Know that all electromagnetic waves travel at the same high speed in a vacuum.
3.3.3Describe typical uses of each region, from radio and television transmission to medical uses of X-rays and gamma rays.
3.3.4Describe the harmful effects of excessive exposure: microwaves heating body cells, infrared burns, ultraviolet damage to skin and eyes, and X-rays and gamma rays causing mutations and cancer.
3.3.5Know that communication with artificial satellites is mainly by microwaves, using low-orbit and geostationary satellites.
3.3.6Supplement: know that electromagnetic waves travel at 3.0 × 10⁸ m/s in a vacuum and at about the same speed in air.
3.3.7Supplement: know how mobile phones, wireless internet, Bluetooth and optical fibres use electromagnetic radiation, and why each region suits its use.
3.3.8Supplement: know the difference between digital and analogue signals.
3.3.9Supplement: know that sound can be sent as a digital or an analogue signal.
3.3.10Supplement: explain the benefits of digital signalling: faster data transmission and longer range thanks to accurate regeneration.

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