Two pressure points in a water pipe are connected to a manometer

Civil UPSC ESE Exam Solution 2021

UPSC ESE Exam Solution 2021 for Civil Engineering UPSC ESE 2021 GS Paper 1 download exam paper from telegram https://telegram.me/civil_experiences

Two pressure points in a water pipe are connected to a manometer which has the form of an inverted U-tube. The space above the water in the two limbs of the manometer is filled with toluene (specific gravity is 0.875). If the difference of level of water columns in the two limbs reads 12.0 cm, what is the corresponding difference of pressure?

(Take g = 9.81 m/s2)

[A] 110.49 N/m²
[B] 128.12 N/m²
[C] 131.34 N/m²
[D] 147.15 N/m²

ANSWER= [D] 147.15 N/m²

Detailed Solution for Civil Engineering Exam

( Pa – Pb ) / γ_w = ( 1 – G2/G1)

( Pa – Pb ) = ( 1 – G2/G1) * γ_w

(Pa – Pb) = ( 1 – 0.875/1 ) * 0.12 * 9810

Pa – Pb = 147.15 N/m²