# A radio station broadcasts signals using electromagnetic waves. The waves travel through the air at a speed of 3 × 10⁸ m/s. One station broadcasts at a frequency of 100 MHz and another broadcasts at a frequency of 200 MHz. Describe the wave properties of frequency and wavelength, and explain how the wavelengths of the two stations' signals compare to each other.

> Eduqas A-Level Physics — 3.1 Wave properties · Describe · 5 marks

> Radio stations broadcast signals as electromagnetic waves. These waves all travel through air at the same speed of 3 × 10⁸ m/s, but different stations broadcast at different frequencies.

## Mark scheme (5 marks)

1. Frequency is the number of complete waves (cycles/oscillations) passing a point per second
2. Wavelength is the distance between two successive (identical/corresponding) points on adjacent waves / the length of one complete wave
3. The wave speed equals frequency multiplied by wavelength (v = fλ), so wavelength and frequency are inversely related at constant speed
4. The 200 MHz station has a higher frequency than the 100 MHz station
5. The 200 MHz station has a shorter wavelength / the 100 MHz station has a longer wavelength (because both travel at the same speed but at different frequencies)

## Key terms

- [frequency](https://www.gradenine.co.uk/glossary/frequency)
- [wavelength](https://www.gradenine.co.uk/glossary/wavelength)
- [electromagnetic waves](https://www.gradenine.co.uk/glossary/electromagnetic-waves)

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-radio-station-broadcasts-signals-using-981124c6) · Published by Druglandscape Ltd.