In the left column of communicating vessels, water is poured into the right-hand kerosene.

In the left column of communicating vessels, water is poured into the right-hand kerosene. The height of the kerosene column is 20cm. Calculate how much the water level in the left column is below the top level of kerosene.

Given:
ρ1 = 1000kg / m ^ 3 – water density,
ρ2 = 800kg / m ^ 3 – density of kerosene,
h2 = 20cm = 0.2m – the height of the kerosene column.
Find h2 – h1, where h1 is the height of the water column.
The hydrostatic pressures of liquids in communicating vessels are:
p1 = p2,
p = ρ * g * h,
ρ1 * g * h1 = ρ2 * g * h2,
ρ1 * h1 = ρ2 * h2,
h1 = ρ2 * h2 / ρ1 = 800 * 0.2m / 1000 = 0.16m;
h2 – h1 = 0.2m – 0.16m = 0.04m = 4cm.