WAEC Physics 2013 Paper

Concept:Liquid pressure is the force exerted per unit area by a liquid, and it changes with depth, density, and gravitational acceleration.Explanation:The pressure $P$ inside a liquid is given by $P = h\rho g$, where $h$ is the depth, $\rho$ is the liquid density, and $g$ is the acceleration due to gravity.At greater depths, the weight of the liquid above that point becomes larger, so the pressure increases.Consider option A: "the pressure in a liquid increases with depth."From the formula, as $h$ increases, $P$ also increases, so this statement is correct.Option B is wrong because a higher density liquid exerts a greater pressure, not a lower one, since $P \propto \rho$.Option C is limited because pressure in a liquid acts in all directions at a point, and it pushes perpendicularly against any surface, not only the sides of the vessel.Option D is wrong because $g$ appears in the formula, so pressure definitely depends on acceleration due to gravity.Therefore, the only true statement about liquid pressure is that it increases with depth.Answer:A. the pressure in a liquid increases with depth