What would a gauge installed at the bottom of a 10-foot deep open water tank indicate in terms of pressure?

To determine the pressure indicated by a gauge installed at the bottom of a 10-foot deep open water tank, one can use the hydrostatic pressure formula, which states that pressure at a certain depth is calculated by the equation:

Pressure (in psi) = Depth (in feet) × 0.433 psi/foot.

This conversion factor of 0.433 psi/foot reflects the weight of water. For a depth of 10 feet, the pressure can be calculated as follows:

Pressure = 10 feet × 0.433 psi/foot = 4.33 psi.

When rounded to one decimal place, this figure is approximately 4.3 psi, which aligns with the correct option provided. This outcome illustrates how hydrostatic pressure operates, showing that the deeper you go in a fluid, the greater the pressure due to the weight of the fluid above. Understanding this concept is essential for interpreting readings from pressure gauges accurately in various practical applications, especially within backflow prevention systems where pressure differentials can be critical.