Chapter 3 · MCQ Read Mode

Fluid Mechanics and Machines

A fluid is a substance that:

The no-slip condition states that at a solid wall the fluid:

The Eulerian method of describing fluid flow:

One poise is equal to:

With an increase in temperature, the viscosity of a liquid:

Blood and paints are examples of:

A fluid which requires a minimum yield stress before it flows, like toothpaste, is a:

The excess pressure inside a soap bubble of diameter d is:

Mercury in a clean glass capillary tube shows:

Standard atmospheric pressure is equivalent to a water column of about:

A piezometer cannot be used to measure:

For a vertical rectangular gate of depth d with its top at the free surface, the centre of pressure is at depth:

A fluid such as sewage sludge or toothpaste, which needs a minimum shear stress before it begins to flow, is called a:

A rising differential pressure across an industrial filter or bag house indicates that:

A flow in which velocity at a point does not change with time is called:

Flow through a long straight pipe of constant diameter at a constant rate is:

Reynolds number is the ratio of:

Flow in a circular pipe is generally laminar when the Reynolds number is less than about:

Water (ν = 1 × 10⁻⁶ m²/s) flows at 0.1 m/s in a 10 mm pipe. The flow is:

Air flow may be treated as incompressible when the Mach number is less than about:

The line traced by dye injected continuously at a fixed point in a flow is a:

In steady flow, streamlines, pathlines and streaklines:

The stream function ψ exists for:

The velocity potential function exists only when the flow is:

Streamlines and equipotential lines intersect each other at:

In a free vortex flow, velocity varies with radius as:

Turbulent flow is generally desirable in a heat exchanger because it:

Sudden closing of a valve in a long water pipeline causes:

Bernoulli's equation is based on the conservation of:

Which is NOT an assumption of Bernoulli's equation?

Water flows from a 200 mm pipe into a 100 mm pipe. If velocity in the larger pipe is 1 m/s, velocity in the smaller pipe is:

The coefficient of discharge of a venturimeter is about:

A pitot tube is used to measure:

The theoretical velocity of a jet from an orifice under a head of 5 m is about:

For a sharp-edged orifice, Cd = Cc × Cv is approximately:

Discharge over a triangular notch is proportional to:

The force exerted by a jet on a stationary flat plate held normal to it is:

According to Buckingham's π-theorem, a problem with 7 variables and 3 fundamental dimensions has:

Ship models and spillway models are designed using:

In a Froude-scaled model with length ratio 1:25, the discharge ratio (model/prototype) is:

Compared with an orifice plate, a venturi meter has:

The flow meter that measures mass flow rate directly and is used for costly process fluids is the:

For laminar flow in a circular pipe, the maximum velocity is:

The friction factor for laminar flow in a pipe at Re = 1600 is:

In laminar pipe flow, the shear stress is:

According to Hagen-Poiseuille, for a given pressure drop the discharge through a pipe varies as:

For laminar flow between two fixed parallel plates, umax/Vavg is:

The Darcy-Weisbach equation gives head loss as:

For pipes connected in parallel:

The head loss due to sudden expansion from velocity V1 to V2 is:

Power transmitted through a pipe is maximum when the friction head loss equals:

Boundary layer thickness is the distance from the wall where velocity reaches:

For a laminar boundary layer on a flat plate, thickness varies with distance x as:

Flow separation occurs when:

Controlling the flow of a centrifugal pump by throttling a discharge valve is inefficient because it:

Frictional head loss in a pipe carrying a given fluid varies approximately with:

A Pelton wheel is a:

A Kaplan turbine is best suited for:

Which turbine is most suitable for a head of 500 m?

The specific speed of a turbine is given by:

In a Pelton wheel, the flow of water is regulated by:

The function of the casing of a Pelton wheel is to:

In a Francis turbine, the guide vanes (wicket gates) serve to:

Double regulation (adjustable guide vanes and runner blades) is a feature of the:

The main function of a turbine governor is to:

Cavitation in a reaction turbine is most likely at the:

A draft tube is used in:

The cone angle of a conical draft tube should not exceed about:

The turbine most widely used in Nepali micro-hydro schemes because it is simple and can be made locally is the:

Cavitation in a hydraulic machine occurs when the local pressure falls:

A centrifugal pump works on the principle of:

The most commonly used impeller blade shape in centrifugal pumps is:

Priming of a centrifugal pump is necessary because:

Which pump does NOT require priming?

A centrifugal pump should be started with the delivery valve:

To avoid cavitation in a pump:

Which action INCREASES the available NPSH?

If the speed of a centrifugal pump is doubled, the head developed becomes:

If pump speed is doubled, the power required becomes:

Two identical pumps connected in parallel will:

The specific speed of a pump is given by:

Negative slip in a reciprocating pump means:

According to the affinity laws, if the speed of a centrifugal pump is reduced to half, the power required becomes about:

A pump running far away from its best efficiency point typically suffers: