(II) The pressure variation in a sound wave is given by
$\Delta P=0.0035 \sin (0.38 \pi x-1350 \pi t)$
where $\Delta P$ is in pascals, $x$ in meters, and $t$ in seconds. Determine $(a)$ the wavelength, $(b)$ the frequency, $(c)$ the speed, and $(d)$ the displacement amplitude of the wave. Assume the density of the medium to be $\rho=2.3 \times 10^{3} \mathrm{kg} / \mathrm{m}^{3} .$