Engineering Questions with Answers - Multiple Choice Questions
Mechanical Operations MCQ’s – Optimum Time Cycle
1 - Question
What does the following equation represents?
Q= K1 ND3
a) Flow of impellor
b) Discharge
c) Velocity
d) Density
View Answer
Answer: a
Explanation: The quantity of flow is defined as the amount of fluid which moves axially or radially away from the impellor at the surface area of rotation.
2 - Question
What does the following equation represents?
P=QρH
a) Density
b) Discharge
c) Velocity
d) Power
View Answer
Answer: d
Explanation: The power requirements cannot always be calculated for a system with great degree of reliability, thus the following equation can be used.
3 - Question
What does the below equation represent?
a) Schmidt number of mixing
b) Froude number of mixing
c) Reynold’s number of mixing
d) Dom number of mixing
View Answer
Answer: c
Explanation: The following represents the Reynold’s number for mixing, where N is the impellor rotational speed and D is the impellor diameter.
4 - Question
What does the following represents?
a) Schmidt number of mixing
b) Froude number of mixing
c) Reynold’s number of mixing
d) Dom number of mixing
View Answer
Answer: b
Explanation: The following represents the Froude number for mixing, where N is the impellor rotational speed and g is the gravitational constant 32.2 ft/sec2.
5 - Question
What does the below equation represent?
a) Schmidt number
b) Froude number
c) Reynold’s number
d) Power number
View Answer
Answer: d
Explanation: The power number PO is used in most of the correlations to represent the relationship to system performance.
6 - Question
What does the following represents?
a) Entrainment
b) Flow rate
c) Discharge
d) Throttle
View Answer
Answer: a
Explanation: From a propeller, the entrainment by the circular jet is given by the above equation, where X is the distance from impellor source not to exceed 100 jet diameters.
7 - Question
The maximum Q/p1/3 for a circular jet is at X= _________
a) 1.71D0
b) 2.5D0
c) 7D0
d) 8.5D0
View Answer
Answer: a
Explanation: The maximum Q/p1/3 for a circular jet is at X=1.71D0 or in other word the optimum jet origin diameter is 1/17.1 of the distance desired for effective entrainment.
8 - Question
What does the below equation represent?
a) Velocity gradient
b) Gravity
c) Centrifugal force
d) Exhaust force
View Answer
Answer: a
Explanation: The above equation represents the velocity gradient, where P is the power dissipated and other terms are dynamic viscosity and volume.
9 - Question
As the velocity gradient increases, the shear force _______
a) Decreases
b) Increases
c) Remains same
d) Constant
View Answer
Answer: b
Explanation: We know that the rate of particulate collision the rate is directly proportional to the velocity gradient, G must be sufficient to furnish desired rate.
10 - Question
Calculate G, if two mercury particles are moving at 2 m/sec to each other at a distance of 10 m?
a) 0.2
b) 5
c) 0.5
d) 2
View Answer
Answer: a
Explanation: We know that G= (2 m/sec) / (10 m) = 0.2 sec-1.