# Civil Engineering - GATE Exam Questions - Discussion

### Discussion :: GATE Exam Questions - Section 1 (Q.No.35)

35.

A water treatment plant is required to process 28800 m3/d of raw water (density = 1000 kg/m3, kinematic viscosity = 10-6 m2/s). The rapid mixing tank imparts tank a velocity gradient of 900s-1 to blend 35 mg/l of alum with the flow for a detention time of 2 minutes. The power input (W) required for rapid mixing is

 [A]. 32.4 [B]. 36 [C]. 324 [D]. 32400

Explanation:

No answer description available for this question.

 Samala Laxman said: (Dec 17, 2013) G = sqrt(power input/volume*dynamic viscosity). Here, G = 900/sec. Q = 28800m^3/day = 0.33m^3/sec. t = 2 min = 120 sec. Volume = Q*t= 40m^3. Dynamic viscosity = kinematic viscosity/density. If we substitute all these values in above formula we will get power = 32400W.

 Kirubakara Raj said: (Aug 16, 2016) Thanks for your explanation @Samala.

 Huidrom said: (Jun 28, 2019) Dynamic viscosity = kinematic viscosity * Density.