In the metric system, the prefixes k, c, m, m and M are often used. A certain bar on a xylophone is 2.5 cm wide and 5 mm thick. Wavelength is the distance traveled by a wave in one oscillation, measured in meters.
Frequency is the number of oscillations per second, measured in Hz.
A transverse wave is a wave in which the displacement is at right angles to the direction of motion of the wave. A longitudinal wave is a wave in which the displacement is in the same direction as the direction of motion of the wave. A periodic motion in which the acceleration is directly proportional to the displacement but in the opposite direction. Hz or 2 kHz .