Answer
$48^{\circ}$.
Work Step by Step
The angle of refraction can be found from the law of refraction, which is equation 11–20. The speeds of the incoming and outgoing sound waves can be found using equation 11-14a.
$$\frac{sin\theta_2}{ sin\theta_1}=\frac{v_2}{v_1}=\frac{\sqrt{E/\rho_2}}{\sqrt{E/\rho_1}}$$
$$=\sqrt{\frac{\rho_1}{\rho_2}}=\sqrt{\frac{SG_1\rho_{water}}{ SG_2\rho_{water}}}=\sqrt{\frac{SG_1}{SG_2}}$$
$$\frac{sin\theta_2}{ sin\theta_1}=\sqrt{\frac{SG_1}{SG_2}}$$
$$ sin\theta_2= sin\theta_1\sqrt{\frac{SG_1}{SG_2}}= sin38^{\circ}\sqrt{\frac{3.6}{2.5}}=0.7388$$
$$ \theta_2= sin^{-1}0.7388\approx 48^{\circ}$$
