Download Aptitude Crack
img not found img not found

UPSC Civil Service Exam Questions - Engineering

Q1:

Two reservoirs at different surface elevations are connected by a set of two pipes A and B of same diameter and length in parallel. If the friction factor of A is 4 times that of the pipe B, what is the ratio of the discharge in A to that in B ?

A 0.25

B 4.0

C 2.0

D 0.5

ANS:C - 2.0

@Santu ans is 2 not 0.5.

f2/f1=1/2.
Q=A/V.
Q1/Q2=4 (v1/v2)^2.
Then elaborate Q1/Q2.

I.e (A1*v1)/(A2/v2)=4 (v1/V2)^then cancel v1/v2 on both sites.
We get,
Then A1/A2=4 [v1/v2].
Hence v1/v2=root of f2/f1 = 1/2.
So, the ans is A1/A2 = 4 * (1/2).
We get the ans 2. So answer c is correct.