What defines a sine wave?

A sine wave is fundamentally defined by its smooth, continuous oscillation, which characterizes its shape and behavior. This wave pattern can be described mathematically by the sine function. In a sine wave, the oscillation occurs in a periodic manner, smoothly transitioning between peaks and troughs without abrupt changes. This continuous nature is essential to understanding various applications of sine waves in fields like audio technology, signal processing, and electrical engineering.

The consistent amplitude mentioned in one of the choices refers more generally to the stability of the wave's height, while a sine wave is inherently defined by the smooth and cyclic nature of its oscillation, which is better captured by the idea of continuous movement. Waves that travel in one direction or exhibit sharp peaks and troughs describe different waveforms or behaviors that do not encapsulate the fundamental attributes of a standard sine wave. Therefore, the most accurate definition is the one highlighting its smooth oscillation.