There is so much physics in music, especially in the performing part with all the different instruments. The guitar for example, uses strings and whatever material is used to make the body, usually wood, to make the actual instrument. Than the strings are attached, aligned, and tuned to that when you press down on the strings on the different frets you change the wave lengths of the standing waves and create different notes. This goes for all string instruments. Other instruments such as trumpets and what not use valves instead of strings to change the wavelengths of the standing waves. How hard you strum a guitar or blow in a trumpet changes the amplitude which is how loud it is.
Musical instruments use a lot of waves and magnetism depending on which ones they are. Guitars (acoustic) use waves which reflect off of different surfaces so we can perceive it. Electric guitars get plugged into guitar amplifiers which are composed of amplifiers, and speakers which are made with magnets and coils.