Question

How tall (in m) must a water-filled manometer be to measure blood pressures as high as 245 mm Hg?

Answer 1

In order to convert the pressure from mmHg to mmH20 (that is, using water instead of mercury), we need to use the following relation:

1 mmHg = 13.6 mmH20

(This relation can be found by calculating the ratio of the densities)

So we have:

`245\text{ mmHg}=245\cdot13.6\text{ mmH20}=3332\text{ mmH20}`

Therefore the water must be 3.332 meters tall.