Question

Why the speed of sound in water is more than mercury, though the density of mercury is more than water?

Answer 1

The speed of sound in liquids depends not only on the density but also on the bulk modulus $K$ . So,

$v=\sqrt{\frac{K}{\rho}}$

$v_{water}=\sqrt{\frac{K}{\rho}}=\sqrt{\frac{2.2\cdot10^9}{1000}}=1483\ (m/s)$

$v_{Hg}=\sqrt{\frac{K}{\rho}}=\sqrt{\frac{25\cdot10^9}{13520}}=1360\ (m/s)$