A key is a specific part of a musical instrument. The purpose and function of the part in question depends on the instrument.
Middle C marks the center of the keyboard. As you will notice the C Major is the easiest and simplest scale of the twelve. In C Major Scale you may play the song “ik pyar kaa nagma hai”. It consists all the white keys from any starting C to the next. C. The diagram 1 below represents the C major scale in all three octaves. C major can be written as ( C maj, CM ).
We usually specify these orders by their harmonic number or multiple of the fundamental frequency. For example, a harmonic with a frequency of 180 Hz is known as the third harmonic (60×3 = 180).
In this case, for every cycle of the fundamental waveform, there are three complete cycles of the harmonic waveforms. The even multiples of the fundamental frequency are known as even-order harmonics while the odd multiples are known as the odd-order harmonics.