1-11When you use the above equation, be careful to express velocity and wavelength in the proper unitsoflength. For example, in the English system, if the velocity (expressed in feetper second) is divided bythe frequency (expressed in cycles per second, or Hz), the wavelength is given in feet per cycle. If themetric system is used and the velocity (expressed in meters per second) is divided by the frequency(expressed in cycles per second), the wavelength is given in meters per cycle. Be sure to express both thewavelength and the frequency in the same units. (Feet per cycle and meters per cycle are normallyabbreviated as feet or meters because one wavelength indicates one cycle.) Because this equation holdstrue for both transverse and longitudinal waves, it is used in the study of both electromagnetic waves andsound waves.Consider the following example. Two cycles of a wave pass a fixed point every second, and thevelocity of the wave train is 4 feet per second. What is the wavelength? The formula for determiningwavelength is as follows:NOTE: In problems of this kind, be sure NOT to confuse wave velocity with frequency.FREQUENCY is the numberofcyclesperunitoftime(Hz). WAVE VELOCITY is the speedwithwhichawavetrainpassesafixedpoint.