What is the bulk modulus of a perfectly rigid body?

Given: $\sigma$ is the compressibility of water,$\rho$ is the density of water,and $K$ is the bulk modulus of water. What is the energy density of water at the bottom of a lake $h$ metre deep?

If a rubber ball is taken to a depth of $200 \ m$ in a pool,its volume decreases by $0.1 \%$. If the density of the water is $1 \times 10^3 \ kg/m^3$ and $g = 10 \ m/s^2$,then the bulk modulus (volume elasticity) in $N/m^2$ will be:

The compressibility of a material is defined as:

How many times more compressible are gases compared to solids?

An external pressure $P$ is applied on a cube at $0^o C$ so that it is equally compressed from all sides. $K$ is the bulk modulus of the material of the cube and $\alpha$ is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by