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Science

An introduction to waves

Amplitude, wavelength and frequency

You should understand what is meant by the amplitude, wavelength and frequency of a wave.

Amplitude

As waves travel, they set up patterns of disturbance. The amplitude of a wave is its maximum disturbance from its undisturbed position. Take care, the amplitude is not the distance between the top and bottom of a wave.

Amplitude and wavelength

Wavelength

The wavelength of a wave is the distance between a point on one wave and the same point on the next wave. It is often easiest to measure this from the crest of one wave to the crest of the next wave, but it doesn't matter where as long as it is the same point in each wave.

Frequency

The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second. The unit of frequency is the hertz (Hz). It is common for kilohertz (kHz), megahertz (MHz) and gigahertz (GHz) to be used when waves have very high frequencies. For example, most people cannot hear a high-pitched sound above 20kHz, radio stations broadcast radio wavesradio waves: Low frequency electromagnetic radiation used to transmit information such as television and radio programmes. with frequencies of about 100MHz, while most wireless computer networks operate at 2.4GHz.

Check your understanding of this section by having a go at this activity.

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