Question

A student wants to find the absolute pressure of water at a point below the surface of water. He has a barometer and a manometer pressure gauge. The barometer reads 1.3152 bar where as the manometer pressure gauge reads 0.3152 bar. What is the absolute pressure? (Assume that pressure at one end of the manometer is atmospheric.)

(a) 1 bar

(b) 1.6304 bar

(c) 0.3152 bar

(d) 1.3152 bar

I got this question in an interview for internship.

I'm obligated to ask this question of Manometer in section Buoyancy and Floatation of Fluid Mechanics

Answer 1

Correct option is (b) 1.6304 bar

For explanation: The options may tempt you to subtract the readings, but the concept of barometer and manometer is important. Barometer measures the atmospheric pressure whereas, the manometer reads the gauge pressure. Hence, we need to add the two values.