The pressure P₁ at the top of a dam and P₂ at a depth h from the top inside water (density ρ) are related as:

1. P₁ > P₂
2. P₁ = P₂
3. P₁ - P₂ = hρg
4. P₂ - P₁ = hρg

The wall of a dam is made thicker at the bottom because :

1. the pressure exerted by a liquid remains the same with its depth
2. the pressure exerted by a liquid decreases with its depth
3. the pressure exerted by a liquid increases with its depth
4. of safety from outer forces.

Hydraulic machines act like a :

1. force subtractor
2. force reducer
3. force multiplier
4. both (a) and (c)

A rectangular cement block has length, breadth and height of 60 cm, 30 cm and 15 cm respectively. Identify the correct position of the block and pressure exerted by it on the ground.

1. Minimum pressure is exerted when breadth and height form the base.
2. Maximum pressure is exerted when breadth and height form the base.
3. Maximum pressure is exerted when length and breadth form the base.
4. Minimum pressure is exerted when length and height form the base.