Question

If the density of mercury is 13.58 g/cc, the pressure of 4 kPa is equivalent to:

1. 100 mm Hg
2. 15.02 mm Hg
3. 60.08 mm Hg
4. 30.04 mm Hg

Answer 1

Correct Answer - Option 4 : 30.04 mm Hg

Concept:

The intensity of pressure is given by P = ρ × g × h

Where, ρ = density of the fluid, and h = is the height of liquid column

Calculation:

Given: 

Density of mercury, ρ = 13.658 g/cc = 13.58 × 10³ kg/m³, Pressure = 4 kPa

Now pressure in terms of mercury column

∵ P = ρ × g × h

4 × 10³ = 13.58 × 10³  × 9.81 × h

h = 0.03004 m

Hence, h = 30.04 mm of Hg