Engineering Questions with Answers - Multiple Choice Questions
Environmental Engineering MCQ’s – Selection of Pumping Units
1 - Question
The plot of total dynamic head and discharge of a pump is called ____________
a) Dynamic head curve
b) System head curve
c) Pump curve
d) Discharge curve
View Answer
Answer: b
Explanation: The plot of total dynamic head and discharge of a pump is called system head curve and each point on it denotes the head which consists of total static head, head loss in suction and delivery pipe.
2 - Question
_______ is the point of intersection of system head curve with the characteristic curve of the pump.
a) Discharge point
b) Operating point
c) Velocity head
d) Pumping point
View Answer
Answer: b
Explanation: The operating point is the point of intersection of system head curve with the head – discharge characteristic curve of the pump. It is also called as operating range.
3 - Question
Which of the following is not included in the friction head?
a) Head Loss in entire length of piping
b) Total static head
c) Head Loss in bend tees
d) Head Loss in valves
View Answer
Answer: b
Explanation: The friction head is the sum of head Loss in the entire length of piping, head Loss in bend tees and head Loss in valves.
Explanation: The friction head is the sum of head Loss in the entire length of piping, head Loss in bend tees and head Loss in valves.
4 - Question
When the pumps are in parallel operation?
a) H = H1 + H2
b) 1/H = 1/H1 +1/ H2
c) Q = Q1 + Q2
d) 1/Q = 1/Q1 + 1/Q2
View Answer
Answer: c
Explanation: When the pumps are in parallel operation, then the total discharge is equal to the sum of the discharges by each pump i.e Q = Q1 + Q2.
5 - Question
When the pumps are in series operation?
a) H = H1 + H2
b) 1/H = 1/H1 +1/ H2
c) Q = Q1 + Q2
d) 1/Q = 1/Q1 + 1/Q2
View Answer
Answer: a
Explanation: When the pumps are in series operation, then at a given discharge, total head is equal to the sum of heads added by each pump i.e H = H1 + H2.
6 - Question
The efficiency of the pump at half load is ____________
a) 50%
b) 70%
c) 80%
d) 100%
View Answer
Answer: b
Explanation: The efficiency of a pump depends on the amount of load. At half load, the efficiency of the pump is 70%.
7 - Question
The efficiency of the pump at quarter load is ____________
a) 50%
b) 70%
c) 80%
d) 100%
View Answer
Answer: a
Explanation: The efficiency of the pump at quarter load is 50% and at full load, the efficiency of the pump is 80%.
8 - Question
The installed capacity of the pump does not depend on which of the following?
a) The maximum rate of hourly demand
b) Balancing storage
c) Power of pump
d) Operation schedule
View Answer
Answer: c
Explanation: The installed capacity of the pump depends on three factors, namely- balancing storage, the maximum rate of hourly demand and the operation schedule. The installed capacity of the pump is kept larger than the maximum rate of demand.
9 - Question
If the diameter of pumping mains decreases, then the total dynamic head will increase.
a) True
b) False
View Answer
Answer: a
Explanation: If the diameter of pumping mains decreases, then the velocity of flow will increase for a given fixed discharge resulting in the increase of friction head loss and velocity head and ultimately increases the total dynamic head.