Answer:
one-fourth of the wavelength
Explanation:
When any wave move form its equilibrium to level to the crest then it covers one-fourth of the wavelength. The waves goes twice to its extreme position, once at the crest and one at the trough.
The midway between the crest and trough is the equilibrium position of the wave. The wave in one cycle covers 360° phase. Here when the wave goes from equilibrium to the crest then the wave covers 90° of the phase.
The given time multiplied by 4 gives the time period of the wave.
