Engineering Questions with Answers - Multiple Choice Questions

# Environmental Engineering MCQ’s – Chemical Clarification

1 - Question

Which of the following represents the coagulant pipe in the following figure? Figure: Flash mixer
a) A
b) B
c) C
d) D

Explanation: ‘A’ represents the coagulant pipe which is used for discharging the coagulant into the flash mixer.

2 - Question

Which of the following represents the device which is used for sludge removal in the following figure? Figure: Flash mixer
a) F
b) E
c) D
d) B

Explanation: ‘D’ represents the drain valve which is used for the removal of sludge from the mixer.

3 - Question

_________ is the average of velocities at a point over a definite period of time. Figure: Flash mixer
a) Mean velocity
b) Relative velocity
d) Temporal mean velocity

Explanation: Temporal mean velocity is the average of velocities at a point over a definite period of time. It is represented by G.

4 - Question

Which of the following goes to the flocculation tank in the following figure? Figure: Flash mixer
a) B
b) C
c) E
d) F

Explanation: ‘B’ represents the outlet of the mixer which goes to the flocculation tank.

5 - Question

Which of the following is the correct expression regarding temporal mean velocity in the following figure? Figure: Flash mixer
a) G = (P/μV)1/2
b) G = (P/μV)
c) G = (P/μV)2
d) G = (Pμ/V)1/2

Explanation: Temporal mean velocity G = (P/μV)1/2, where P is the power, μ is the dynamic viscosity and V is the volume of the tank. It is measured in per second.

6 - Question

Which of the following is correctly paired in the following figure? Figure: Flash mixer
a) C – Impeller
b) D – Outlet
c) F – Deflecting wall
d) E – Impeller

Explanation: E represents the Impeller which is driven by the electric motor to revolve in the tank.

7 - Question

The speed of impeller in a flash mixer is ___________ Figure: Flash mixer
a) 45rpm
b) 60rpm
c) 110rpm
d) 200rpm

Explanation: The speed of impeller in a flash mixer is between 100 to 120 rpm and the propeller type impeller is used.

8 - Question

C’ in the following figure represents the ________ Figure: Flash mixer
a) Impeller
b) Impeller shaft
c) Deflecting wall
d) Flash mixer wall

Explanation: ‘C’ represents the deflecting wall, whereas the boundary below the inlet and outlet of the tank is the flash mixer wall.

9 - Question

. The detention period of a flash mixer is _________________ Figure: Flash mixer
a) 2 minutes
b) 30 minutes
c) 1 hour
d) 2 hours

Explanation: The detention period of flash mixer lies between 30 seconds to 2 minutes.

10 - Question

Which of the following represents the impeller shaft in the following figure? Figure: Flash mixer
a) F
b) E
c) C
d) B