A sound wave is passing through the air column in the form of compression and rarefaction. In consecutive compressions and rarefactions,

1. density remains constant

2. Boyle's law is obeyed

3. bulk modulus of air oscillates

4. there is no transfer of heat

(4) Hint: The sound waves are pressure waves.
1. Due to compression and rarefactions, the density of the medium (air) changes. At compressed regions, the density is maximum and at rarefactions, the density is minimum.
2. As the density is changing, so Boyle's law is not obeyed.
3. Bulk modulus remains the same.
4. The time of compression and rarefaction is too small i.e., we can assume an adiabatic process and hence no transfer of heat.