The Electromagnetic Spectrum — Overview

This lesson introduces the electromagnetic (EM) spectrum — the continuous range of electromagnetic waves ordered by wavelength and frequency — as required by AQA GCSE Combined Science Trilogy (8464), Physics Paper 2, section 6.2. You must know the order of the EM spectrum, the shared properties of all EM waves, and how wavelength and frequency are related.

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What Are Electromagnetic Waves?

Electromagnetic waves are transverse waves that:

• Transfer energy from one place to another.
• Can travel through a vacuum (empty space) — they do not need a medium.
• All travel at the same speed in a vacuum: $3 \times 10^{8}$3×108 m/s (the speed of light).
• Consist of oscillating electric and magnetic fields at right angles to each other and to the direction of energy transfer.

Exam Tip (AQA 8464): All electromagnetic waves travel at the same speed in a vacuum. This is the speed of light, approximately $3 \times 10^{8}$3×108 m/s. They differ in their wavelength and frequency.

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The Order of the EM Spectrum

The electromagnetic spectrum is divided into seven main regions. You must learn these in order: