Assessment and Qualifications Alliance (AQA) GCSE Physics Practice Exam 2025 - Free Physics Practice Questions and Study Guide

The term that describes the horizontal distance between the crests of two adjacent waves is known as wavelength. Wavelength is a fundamental property of waves, indicating the distance over which the wave's shape repeats. In the context of transverse waves, such as light or water waves, it directly measures the distance between two successive peaks (crests) or troughs.

Amplitude refers to the maximum displacement of points from their rest position in a wave, which relates to the energy carried by the wave but does not address the distance between crests. Frequency, on the other hand, indicates how many waves pass a specific point in a given time period and is not concerned with spatial measurements. Lastly, the period of a wave refers to the time it takes for one complete wave cycle to pass a given point, further illustrating the temporal rather than spatial nature of wave characteristics.

Thus, wavelength is the correct term for the distance between crests of adjacent waves.