This happens as a result of each вЂњstage of oscillationвЂќ traveling a distance of one wavelength during one period to end up at a point that was at the same stage of oscillation one period earlier. Since a wave undergoes one complete oscillation during one period, all points in the wave return back to the same values after one period. Since frequency measures the number of times that a wave oscillates per unit time, it follows that Period is the time taken for one complete oscillation. Period ( )В is another quantity that we can use to characterize a wave. Clearly, there is a relationship between wavelength and frequency and now we will try to find out exactly what this relationship is. As you do this, you will notice that the wavelength of the wave becomes shorter. You could create a wave with a higher frequency on a rope by wiggling up and down at a faster rate. What is the relationship between Wavelength and Frequency Sounds with frequencies lower than the audible range is called infrasound and the sounds withВ frequencies above the human hearing range are called ultrasound. Humans can hear sounds with frequencies between about 20 вЂ“ 20000 Hz. The note middle D which has a higher pitch than the middle C has a frequency ofВ 293.66 Hz. This means that to produce this note, molecules creating or transmitting the sound wave should oscillateВ 261.63 times every second. For instance, the вЂњmiddle CвЂќ note is a sound wave with a frequency ofВ 261.63 Hz. The higher the frequency, the higher is the pitch. For sound waves, the frequency is related to the pitch of the sound. Often, we use the Greek letter lambda ( ) to represent the wavelength of a wave:ДЇrequency ( ) is the number of complete oscillations that a wave undergoes per unit time. Thus, two adjacent peaks or two adjacent troughs on a wave are separated by a distance of one wavelength. Wavelength is the distance between the two closest points that are in phase with each otherВ along a wave. Such points, which are always at the same stage in oscillation are said to be in phase with each other. For instance, two points on the wave that reach their maximum value in oscillation simultaneously are oscillating in unison. If the wave in question is not just a short pulse, then at any given time, there can be several points on a wave that are at the same stage of oscillation. If you take an electromagnetic wave, the value of electric and magnetic fields due to the wave at a point is always changing. For example, if you create a wave by wiggling a rope up and down, then the molecules that make up the rope are repeatedly moving up and down. That is, every point on a wave shows some kind of regular, repetitive change in some value. To recap every point on a wave is oscillating.

We have discussed what wavelength means when we were discussing the difference between Wavelength and Period. The relationshipВ between wavelength and frequency is that the frequency of a wave multiplied by its wavelength gives the speed of the wave, as we will see below.

Wavelength and frequency are two such characteristics. Waves can be described using a number of different characteristics of a wave.

Frequency of note c