How high should the oil column be to balance the 16 cm high mercury column in the communicating vessels?

To find out the required height of the oil column, we will use the ratio: ρн / ρрт = hрт / hн, from where we express: hн = hрт * ρрт / ρн.

Const: ρн – oil density (ρн = 650 … 1050 kg / m3; assumed ρн = 850 kg / m3); ρрт – density of mercury (ρрт = 13546 kg / m3, assumed ρрт ≈ 13600 kg / m3).

Data: hрт – known height of the mercury column (hрт = 16 cm).

Let’s perform the calculation: hн = hрт * ρрт / ρн = 16 * 13600/850 = 256 cm.

Answer: The oil column should be 256 cm high.