Q1. A continuous, single-frequency sound wave emanates from the position (y=0 mm, z=0 mm). The pressure amplitude at position (y=0 mm, z=10 mm) is 1 kPa. What is the pressure amplitude at the position (y=0 mm, z=100 mm) if the sound wave is (a) spherically spreading, or (b) a plane wave propagating in the +z direction?

Fig: 1