Cambridge O Level Physics · Syllabus 5054 · Waves
Wavefront
What is Wavefront?
A wavefront is a line or surface joining points of a wave that are all in phase, such as a line of crests; wavefronts are drawn perpendicular to the direction of travel and one wavelength apart.
This definition is part of the Waves chapter in Cambridge O Level Physics.
Common mistakes with Wavefront
- 5. “Refraction occurs because the amplitude changes.” Why wrongAmplitude controls how much energy the wave carries. It has no influence on direction; a very quiet and a very loud sound refract identically. CorrectRefraction is caused by a change of speed. A wavefront arriving obliquely pivots because one end slows before the other. Say this“Refraction occurs because the wave changes speed at the boundary.” CheckState the one quantity whose change causes refraction.
- 10. “Light always bends when it crosses a boundary.” Why wrongBending needs an oblique wavefront so that one end slows before the other. A wavefront arriving square-on slows all at once. CorrectAt normal incidence (\(i = 0^\circ\)) the speed and wavelength change but the direction does not. Say this“A ray travelling along the normal is not deviated, although its speed and wavelength do change.” CheckWhy is a ray aimed at the centre of the flat face of a semicircular block not bent at the curved surface?
Last reviewed Syllabus 2026-2028