Chapter 3 · MCQ Read Mode

Fluid Mechanics and Mechanical operations

A fluid is defined as a substance that

An ideal fluid is one which is

The SI unit of dynamic viscosity is

One poise is equal to

With an increase in temperature, the viscosity of a liquid and that of a gas respectively

A fluid whose apparent viscosity decreases with increasing shear rate is called

Toothpaste and drilling mud, which do not flow until a certain minimum shear stress is exceeded, are examples of

A fluid whose apparent viscosity decreases with time at a constant rate of shear is

Kinematic viscosity is defined as

The excess pressure inside a soap bubble of radius R and surface tension sigma is

Capillary rise in a small vertical tube is

Pascal's law states that the pressure at a point in a fluid at rest

For a U-tube manometer with manometric fluid of density rho-m, process fluid of density rho and reading R, the pressure difference is

The centre of pressure on a plane surface submerged in a liquid always lies

A floating body is in stable equilibrium when

In steady flow, streamlines, pathlines and streaklines are

For laminar flow in a circular pipe, the ratio of maximum to average velocity is

According to the Hagen-Poiseuille equation, for a fixed pressure drop the volumetric flow rate through a pipe varies as

The velocity potential function exists only when the flow is

The stream function is defined for

Boundary layer separation occurs because of

Bernoulli's equation in its classical form is NOT applicable when

The kinetic energy correction factor for fully developed laminar flow in a pipe is

Compressibility effects may normally be neglected when the Mach number is below about

In a converging-diverging nozzle operating with supersonic exit flow, sonic velocity is reached

According to the Buckingham pi theorem, a problem involving 7 variables and 3 fundamental dimensions can be described by

The Darcy friction factor is related to the Fanning friction factor by

For laminar flow in a pipe, the friction factor depends on

In fully developed rough-pipe turbulent flow, the friction factor is

The equivalent diameter for flow through an annulus of outer diameter Do and inner diameter Di is

The loss coefficient K for a pipe discharging into a large reservoir is approximately

Which valve, when fully open, offers the least resistance to flow?

In a venturi meter compared with an orifice meter of the same throat ratio, the permanent pressure loss is

In a head-type flow meter, the flow rate is proportional to

A rotameter is classified as a

A Pitot tube is used to measure

If the speed of a centrifugal pump is doubled, the power required changes by a factor of

Cavitation in a centrifugal pump can be avoided by ensuring that

In a fully baffled agitated vessel operating in the turbulent regime, the power number is

The sphericity of a cube is approximately

In the Tyler standard screen series, successive screen apertures are in the ratio of

A material described as minus 14 plus 20 mesh is one which

Rittinger's law of crushing states that the energy required is proportional to

Kick's law is most applicable to

The Bond work index is defined as the energy required to reduce a very large feed to a product in which 80 per cent passes

If a ball mill is operated at or above its critical speed

The angle of nip in a roll crusher must not exceed

Which of the following mills produces an ultrafine product with essentially no moving parts in the grinding zone?

Compared with dry grinding, wet grinding generally

Closed-circuit grinding is preferred to open-circuit grinding because it

A bucket elevator is used primarily for

In dilute-phase pneumatic conveying, the solids are

Screening separates particles on the basis of

The effectiveness of a screen based on the undersize is given by

As the feed rate to a screen is increased, its capacity and effectiveness respectively

Blinding of a screen refers to

In a differential screen analysis, the number of particles per unit mass in a size interval varies as

The volume-surface or Sauter mean diameter is calculated as

Elutriation separates particles on the basis of

Froth flotation separates minerals principally by differences in

In froth flotation, the reagent whose function is to make the mineral surface hydrophobic is the

Copper sulphate added to a flotation circuit to make sphalerite respond to a xanthate collector acts as

Jigging separates particles principally on the basis of

Electrostatic separation of beach sands exploits differences in

Compared with free settling, hindered settling gives

According to Stokes' law, the terminal settling velocity of a small spherical particle is proportional to

Stokes' law for settling is valid when the particle Reynolds number is

In the Newton's law region of settling, the drag coefficient is approximately

The purpose of adding alum to a dilute suspension before sedimentation is to

In a continuous thickener, the required cross-sectional area is determined by

At the minimum fluidization velocity, the pressure drop across the bed equals

As the fluid velocity is increased beyond the minimum fluidization velocity, the pressure drop across the bed

The Ergun equation for flow through a packed bed contains

Gas-solid fluidization in which the gas passes through the bed as bubbles within a dense emulsion phase is called

The upper limit of the operating velocity range for a fluidized bed is set by

In constant-pressure filtration, a plot of t/V against V yields a straight line whose slope is proportional to

For a compressible filter cake, doubling the applied pressure difference

The correct sequence of zones encountered by a point on the surface of a rotary drum vacuum filter during one revolution is