Question

In the U tube manometer, if we use water as the liquid instead of mercury, you can get the height difference by doing which one of the following to an equivalent mercury expression for obtaining the pressure?

• A. Multiplying by 13.6
• B. Subtracting 13.6
  
• C. Adding 13.6
• D. Dividing by 13.6

Answer 1

Answer: (D)

Dividing by 13.6

In the U tube manometer, if we use water as the liquid instead of mercury, you can get the height difference by dividing by 13.6 to an equivalent mercury expression for obtaining the pressure.
The density of $Hg$ and water are 13.6 $g/mL$ and 1 $g/mL$ respectively.
Also pressure is obtained by multiplying height difference with density and acceleration due to gravity.
$P=h\rho g$