Talk:Waves/Geometrical optics Introduction

At high frequencies, or more specifically when the wavelength is small compared to other geometrical features, sound behaves as if it travels along rays, just like light rays. A flashlight beam is a good example of a bundle of light rays. This aspect of wave behavior is called geometrical optics because one can analyze things (such as telescope mirrors) by geometrically tracing rays, rather than solving a wave equation.