28. The wall of a dam is made thicker at the bottom than the top because the pressure exerted by the water on the wall :

(A) depends on the thickness of the wall

(B) increases with height of the wall

(C) increases with depth of the wall

(D) depends in the area of the wall

Ans. (C) increases with depth of the wall

Dams are built broader at the base for two reasons. The first is because it needs to be stable enough to support the dam, and two, the bottom of the dam needs to be able to deal with the increased pressure of the water, as you get further down. Water pressure is greater at the base than the surface.