State one difference between a musical note and noise.

Hint: Periodicity plays an important role in understanding musical notes and noise. Musical notes are regular and have an accurate pattern. Musical notes are pleasing to our minds and ears. On the other hand, noise is a kind of disturbance and is irregular. It is more like an unwanted sound.

Complete answer:
The difference between musical note and noise can be explained in both theoretical and mathematical ways.
Theoretically, we can say that music notes are ordered sound whereas noise is disordered sound.
Mathematically, we can say that both music and noise both are mixtures of sound waves having different frequencies. In music the frequencies are discrete that means separable, whereas noise frequencies are continuous and random with no regular pattern.

Additional information:
Musical notes are well organized and made by humans in order to accomplish something or to communicate or deliver some message through that music. Noise is the arrangement of sound done deliberately by humans which seems unpleasant to human ears. Generally speaking music has always some meaning within it while noise has no intention at all.

Note:
Musical notes are produced by regular periodic vibration of the body and thus the amplitude and frequency of vibration does not change. On the other hand noise is produced by irregular periodic vibration of the body and hence it’s amplitude and frequency of vibration changes continuously. Musical notes have repetitive structure while noise has no proper repetition and is vague. Noise is also a kind of sound that is not good to hear.