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
View Answer
Answer: a
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
View Answer
Answer: c
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
c) Velocity gradient
d) Temporal mean velocity
View Answer
Answer: d
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
View Answer
Answer: b
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
View Answer
Answer: a
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
View Answer
Answer: d
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
View Answer
Answer: c
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
View Answer
Answer: c
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
View Answer
Answer: a
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
View Answer
Answer: a
Explanation: Impeller is connected to impeller shaft which is further connected to electric motor so as to drive the impeller and mixing of coagulant in water takes place.