Question

Pressure at a depth of 15 m under water surface in a dam is approximately
1. 15 bar
2. 1.5 MPa
3. 150 kPa
4. None of these

Answer 1

Correct Answer - Option 3 : 150 kPa

Concept:

• The normal force exerted by liquid at rest on a given surface in contact is called the thrust of liquid on that surface.
• The normal force (or thrust) exerted by liquid at rest per unit area of the surface in contact with it, is called pressure of liquid or hydrostatic pressure.
• If P is the pressure for a point at depth h below the surface of a liquid of density ρ.

Hydrostatic pressure P is given by P = ρgh

Calculation:

Given:

Height (h) = 15 m and density of water (ρ) = 103 kg/m3

The pressure at a depth of 15 m is:

⇒ Pa = ρgh 

⇒ Pa = 103 × 10 × 15 =  150 kPa         

Hence the required pressure at the given depth is 150 kPa.