It is not only Physics that is involved in Music, all forms of basic sciences like mathematics, chemistry, computers and Electronics are used in decoding various aspects of music.
Swarakalpana by a musician is nothing but pure mathematical calculation. Why go till swarkalpana, the sarlevarises sung in first second and third speeds involve mathematics in it, in the sense that single note fits in a single beat, in the first speed, 2 notes in a beat in the second speed and 4 of them in a beat in the third tempo. Thus the journey of basic mathematics has already begun. Rhythm is full of complex mathematics, the details of which can be a whole big article by itself. A mridangist plays mridangam with complex calculations of the beats to fit in a given frame of taaLa. Different taaLas have different numbers of notes to be fitted in which is a mere mathematical calculation.
The basic instrument, tambura involves mathematics, as the differences in shruti/frequency are nothing but a complex number chart.
Refer http://www.shadjamadhyam.com/saptak_tanpura_harmonics for detailed numbers.
Not only mathematics, chemistry also enters music in the manufacturing of instruments. Mridangam uses layers of mixture of iron oxide or manganese with cooked rice on its right side, for proper tuning requirements. Violin uses rosin(source:Wikipedia; Rosin, also called colophony or Greek pitch, is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components) to grip the strings and make them vibrate clearly. If one has the interest in studying the making of instruments, a lot of examples can be quoted.
Needless to mention that today’s technology uses a lot of electronic devices and computers to create a new wave in the field of music, be it Carnatic or contemporary music.
Psychology and Music, I must say, are inseparable. Music plays a very important role in changing the moods and emotions of an individual, be it the singer or the listener. The title “Psychology and Music” is a chapter of discussion by itself, which I would like to discuss subsequently under a separate title as it is a topic of special interest to me.