361. A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now
Increase
Decrease
Remain same
Data insufficient to predict
✅ The correct answer is option B.
Fluid Mechanics MCQs
362. The pressure intensity is the same in all directions at a point in a fluid
Only when the fluid is frictionless
Only when the fluid is at rest having zero velocity
When there is no motion of one fluid layer relative to an adjacent layer
Regardless of the motion of one fluid layer relative to an adjacent layer
✅ The correct answer is option C.
363. In the laminar boundary layer flow over a flat plate, the ratio (δ/x) varies as :(where, ‘δ’ is the boundary layer thickness and ‘x’ is the distance from the leading edge in the direction of flow).
Re
√Re
1/Re
Re-1/2
✅ The correct answer is option D.
364. Prandtl mixing length is
Applicable to laminar flow problems
A universal constant
Zero at the pipe wall
None of these
✅ The correct answer is option C.
365. In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of
Relative roughness
Absolute roughness
Friction co-efficient for flows at equal Reynold number
All of the above
✅ The correct answer is option C.
366. Reciprocating pumps compared to centrifugal pumps
Deliver liquid at uniform pressure
Can handle slurries more efficiently
Are not subject to air binding
Can be operated with delivery valve closed
✅ The correct answer is option C.
367. A floating/submerged body is always stable, if its centre of gravity
Lies above its centre of buoyancy
And centre of buoyancy coincide
Lies below its centre of buoyancy
Lies above its meta centre
✅ The correct answer is option C.
368. Which law is followed by the velocity distribution in the turbulent boundary layer?
Parabolic law
Linear law
Logarithmic law
None of these
✅ The correct answer is option C.
369. For flow of fluids through packed bed, the superficial velocity is
Less than the average velocity through channels
More than the average velocity through channels
Dependent on the pressure drop across the bed
Same as the average velocity through channels
✅ The correct answer is option A.
370. A venturimeter measures the
Velocity head
Pressure
Point velocity
None of these
✅ The correct answer is option D.