Mechanical Operations Questions and Answers – Optimum Time Cycle

This set of Mechanical Operations Multiple Choice Questions & Answers (MCQs) focuses on “Optimum Time Cycle”.

1. 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. 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. What does the below equation represent?
The Reynold’s number for mixing where N is rotational speed & D is diameter

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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. What does the following represents?

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Froude number for mixing N is impellor rotational speed & g is gravitational constant
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. What does the below equation represent?
The power number PO used in correlations to represent relationship to system performance

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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. What does the following represents?
The entrainment by the circular jet is given by above equation, where X is the distance

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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. 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. What does the below equation represent?

The above equation represents the velocity gradient, where P is the power dissipated

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. 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. 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.

Sanfoundry Global Education & Learning Series – Mechanical Operations.

To practice all areas of Mechanical Operations, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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