Engineering Questions with Answers - Multiple Choice Questions

MCQs on Power Absorbed in Viscous Flow

1 - Question

During which case will the power loss be maximum?
a) High viscosity oil
b) Low viscosity oil
c) High viscosity water
d) Low viscosity water

View Answer

a
Explanation: A highly viscous oil will offer greater resistance due to which the power loss is maximum. As we know, oil has a greater density than water. Thus, oil is more viscous than water and corresponds to a higher loss of power.




2 - Question

Angular speed of the shaft is________
a) 2πN/1000
b) 2πN/60
c) 2π/N
d) 2N/60

View Answer

b
Explanation: Angular speed is defined as the rate at which an object changes its angles. The angle can be measured in radians. Angular speed is a scalar quantity. It is measured within a given time period.




3 - Question

Tangential speed of the shaft is______
a) 2πN/1000
b) πDN/1000
c) πDN/60
d) 2πN/60

View Answer

c
Explanation: Tangential speed is defined as the distance travelled per unit time. It is a linear speed of something that moves around a circular path. Example of tangential speed is a point on the edge of a merry-go-round. The merry-go-round travels a greater distance in one complete rotation than the point near the centre.




4 - Question

Fluid does not offer resistance to change of__________
a) Temperature
b) Volume
c) Pressure
d) Shape

View Answer

d
Explanation: Shape is one of the most important factors for a fluid. The forces other than gravity that fall on the fluid affects the outcome. Thus, changing the shape of the fluid cannot be controlled.




5 - Question

If a fluid does not undergo any sort of resistance by displacement. What substance is it called?
a) Ideal fluid
b) Solid
c) Gas
d) Water

View Answer

a
Explanation: An ideal fluid is a fluid that has zero viscosity. It results in a flow called as inviscid flow. In this flow there is no existence of shear force and the viscosity vanishes.




6 - Question

Why can’t mercury wet a glass?
a) Cohesion
b) Adhesion
c) Surface tension
d) Compressibility

View Answer

c
Explanation: Surface tension is an elastic tendency of a fluid. It results due to imbalance of intermolecular attractive forces. Any molecule at the surface of the liquid experiences a net inward force. Mercury having a higher density than water, cannot wet a glass.




7 - Question

What is the unit of power absorbed in a fluid?
a) Ampere
b) Volt/m
c) kgm2s-3
d) kg/m

View Answer

c
Explanation: Unit of power is a Watt. This is in accordance with the SI unit. The International system of units define it as 1 joule per second. Therefore, the SI base unit is kgm2s-3. It was named after James Watt.




8 - Question

One horse power is__________
a) 7460 W
b) 746 kW
c) 746 W
d) 0.746 W

View Answer

c
Explanation: Horse power is defined as the unit of foot-pound-second. Foot-pound-second(fps) is a unit in accordance with the English system. One horse power is equal to 550 fps/s. Thus, the power relation is 1HP= 746W.

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