# Civil Engineering - GATE Exam Questions - Discussion

Discussion Forum : GATE Exam Questions - Section 2 (Q.No. 38)
38.
Three reservoirs A, B and C are interconnected by pipes as shown in the below figure Water surface elevations in the reservoirs and the Piezometric Head at the junction J are indicated in the below figure.

Discharges Q1, Q2 and Q3 are related as
Q1 + Q2 = Q3
Q1 = Q2 + Q3
Q2 = Q1 + Q3
Q1 + Q2 + Q3 = 0
Explanation:
No answer description is available. Let's discuss.
Discussion:
9 comments Page 1 of 1.

Sneha Mathai said:   4 years ago
Ans is option A.

Flow takes place from higher energy level to lower energy level.
So flow from A to jn.

So flow from B to jn.

So flow from jn to C.

Hence, Q1 + Q2 = Q3.

NILADRI ROY said:   4 years ago
Q1+Q2=Q3.

ABHISHEK RAAZ said:   4 years ago
At junction point J velocity head will be zero so total head at J will be 160 m. The total head at A=200m and total head at B=180m and total head at C=140 m. Now you can judge flow condition from higher energy levels to lower levels.

Dipesh said:   5 years ago
But piezometer level only shows p/(density)g + z.

It doesn't show v^2/2g. So it's not total head then how can we make judgement without velocity head?

Saini said:   5 years ago
Option A is correct. I also agree.

Yogesh said:   6 years ago
Option A is correct.

Q1 takes place from 200 to J (160),
Q2 takes place from 180 to J (160),
Q3 takes place from J (160) to 140.

So Q3 = Q1 + Q2.