how is a stationary wave formed
Stationary Waves. Stationary or standing waves are formed in a medium when two waves having equal amplitude and frequency moving in opposite directions along the same line, interfere in a confined space. Generally, such waves are formed by the superposition of a forward wave and the reflected wave. Both longitudinal and transverse types of waves can form a stationary wave. When reflection occurs at a free end, there is no reversal of phase. i.e., a crest returns as a crest and a trough as a trough.