Waves, light and the electromagnetic spectrum: study guide - CCEA GCSE Physics

Waves and light run across both units of CCEA GCSE Physics. The topic blends a calculation strand (the wave equation, echoes) with descriptive work on light behaviour and the electromagnetic spectrum.

What this topic covers

• Wave properties and the wave equation - transverse and longitudinal waves, the wave terms, and $v = f\lambda$.
• Sound and ultrasound - sound as a longitudinal wave, pitch and loudness, the hearing range, and uses of ultrasound including echo sounding.
• Reflection and refraction - the law of reflection, refraction as a change of speed and direction, and total internal reflection.
• Lenses and the eye - converging and diverging lenses, image formation, the eye, and correcting short and long sight.
• The electromagnetic spectrum - the order of the spectrum, the shared properties of EM waves, and the uses and hazards of each region.

How it is examined

Expect wave-equation and echo calculations, ray diagrams and descriptions of reflection and refraction, questions on lenses and sight defects, and recall of the EM spectrum with a use or hazard for each region. Diagrams must show the normal and correctly labelled angles.

The equation to recall

• Wave speed: $v = f\lambda$.

(For echoes, remember the pulse travels there and back, so halve the total distance.)

How to revise it

1. Drill the wave equation. Practise rearranging it and converting kHz and MHz to Hz.
2. Practise echo problems. Always halve the distance for there-and-back trips.
3. Master ray diagrams. Draw the normal, then apply the law of reflection or the refraction rules.
4. Learn the lens and eye facts. Know which lens corrects each sight defect and why.
5. Memorise the EM spectrum. Learn the order and a use and hazard for each region.

Work through the linked dot points for full worked answers and exam-style questions on each part of the topic.