Acoustic impedance- pressure and velocity

[iVenky]

I find that the acoustic impedance is given by

Z= Pressure/ Velocity


I read that the acoustic impedance of a plane propagating wave is given by

Z = ρ₀c.

What is ρ₀ and c?

Thanks a lot

 

[Bobbywhy]

c=speed of sound
ρ0 = density