A cube is shifted to a depth of 100 m is a lake. The change in volume is 0.1%. The bulk modulus of the material is nearly

10 m column of water exerts nearly l atmosphere pressure. So, 100 m column of water exerts nearly 10 atmosphere pressure, 

            i.e., 10 × ${10}^5$Pa    or      ${10}^6$ Pa. Now,

$K=\frac{\left(\Delta P\right)V}{\Delta V}=\frac{{10}^6\times 100}{0.1}Pa={10}^{9}Pa$