Waves Study Guide

Ultrasound refers to sound waves with frequencies that are higher than the upper limit of human hearing. The average human ear can typically detect sound frequencies ranging from approximately 20 hertz (Hz) up to 20,000 hertz (20 kHz). Therefore, any sound wave that has a frequency exceeding 20,000 Hz is classified as ultrasound. These high-frequency sound waves have many applications, including medical imaging and industrial inspections, because they can be precisely directed and reflected by different materials.

Waves are disturbances that transfer energy without the net transfer of matter. To describe and quantify waves, several key terms are used: amplitude, period, wave velocity, and wavefront. Amplitude refers to the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. It's directly related to the energy carried by the wave. The period is the time it takes for one complete wave cycle or oscillation to pass a given point. Wave velocity is the speed at which the wave energy travels through a medium. A wavefront is an imaginary surface joining points of constant phase on a wave, perpendicular to the direction of energy propagation. These terms are fundamental to understanding the behaviour and properties of all types of waves, from sound to light.