You fill a vertical glass tube to a depth of 15.0 cm with freshwater. You then pour on top of the water an additional 15.0 cm of gasoline (density 7.40×102kg/m3), which does not mix with water. The upper surface of the gasoline is exposed to the air. Find the gauge pressure at the interface between the gasoline and water.

1087.8 Pa

Explanation:

given that:

You fill a vertical glass tube to a depth of 15.0 cm with freshwater.

i.e Height (h₁) of the tube = 15.0 cm =0.15 m

Additional 15.0 cm of gasoline was added  = 0.15 m

the density of the gasoline  = 7.40×10² kg/m³ = 740 kg/m³

acceleration due to gravity (g) = 9.8 g

the gauge pressure at the interface between the gasoline and water can be determined as =

= 740 × 9.8 × 0.15

= 1087.8 Pa

Thus, the gauge pressure at the interface between the gasoline and water =  1087.8 Pa