Fluid Mechanics Practice Level -1 - Class 11 MCQ

An ornament weighing 36 g in air weights only 34 g inwater. Assuming that some copper is mixed with goldto prepare the ornament, find the amount of copper init. Specific garvity of gold is 19.3 and that of copper is8.9

Water flows through a horizontal tube as shown in thefigure. If the difference of heights of water column in thevertical tubes is h = 0.02 m. and the area of crosssection at A and B are 4 × 10^-4 m² and 2 × 10^-4 m²,respectively, then the rate of flow of water across anysection is

In a U-tube in which the cross-sectional area of thelimb on the left is one-quater, the limb on the containsmercury (density 13.6 g/cm³), and the level of mercuryin the narrow limb is at a distance of 36 cm from theupper end of the tube. What will be the rise in the levelof mercury in the right limb if the left limb is filled to thetop with water?

We have two different liquids A and B whose relative iensities are 0.75 and 1.0, respectively. If we dip solid objects P and Q having relative densities 0.6 and 0.9 in these liquids, then
 

A cubical block of wood of side a and density ρ floats in water of density 2 ρ . The lower surface of the cube just touches the free end of a massless spring of force constant K fixed at the bottom of the vessel. The weight W put over the block so that it is completely immersed
in water without wetting the weight is

When at rest, a liquid stands at the same level in the‘tubes as shown in the figure. But as indicated, a heightdifference h occurs when the system is given anacceleration 'a' towards the right. Then h is equal to

Three liquids having densities 1 2 ρ ρ and 3 ρ are filled ina U-tube. Length of each liquid column is equal to I,1 2 3 ρ > ρ > ρ liquids remain at rest (relative to thetube) in the position shown in the figure. It is possiblethat

A beaker containing water is placed on the platform of a spring balance. The balance reads 1.5 kg. A stone of mass 0.5 kg and density 104 kg/m3 is immersed in water without touching the walls of the beaker. What will be the balance reading now?
 

“figure shows a capillary tube C dipped in a liquid thatwets The liquid rises to a point A. If we blow air throughthe horizontal tube H, what will happen to the liquidcolumn in the capillary tube?

A tank is filled with water of density 10³ kg/m³ and oilof density 9 X 10³ kg/m³. The height of water layer is 1m and that of the oil layer is 4 m. The velocity of effluxfrom an opening in the bottom of the tank is

A hole is made at the bottom of a tank filled with water(density = 10³ kg/m³). If the total pressure at the bottomof the tank is 3 atm (1 atm = 10⁵ N/m²), then the velocityof efflux is

The opening near the bottom of the vessel shown infigure has an area A. A disc is held against the openingto keep the liquid from running out. Let F₁ be the netforce on the disc applied by liquid and air in this case.Now the disc is moved away from the opening a shortdistance. The liquid comes out and strikes the discinelastically. Let F₂ be the force exerted by the liquid inthis condition. Then F₁ / F₂ is

There are two identical small holes of area of crosssection a on the opposite sides of a tank containing aliquid ‘of density ρ . The difference in height betweenthe holes is h. The tank is resting on a smoothhorizontal surface. The horizontal force which will haveto be applied on the tank to keep it in equilibrium is

Equal volume of two immiscible liquids of densities rand are 2 ρ filled in a vessel as shown in the figure.Two small holes are punched at depths h/2 and 3h/2from the surface of lighter liquid. If v₁ and v₂ are thevelocities of efflux at these two holes, then v₁/v₂ is

In a cylindrical water tank there are two small holes Qand P on the wall at a depth of h₁, from the upper levelof water and at a height of h₂ from the lower end of thetank, respectively, as shown in the figure. Water comingout from both the holes strike the ground at the samepoint. The ratio of h₁ and h₂ is

Figure shows a liquid flowing through a tube at thefate of 0.1 m³/s. The tube is branched into twosemicircular tubes of cross-sectional area A/3 and24/3. The velocity of liquid at Q is (the cross section ofthe main tube is A = 10² m² and v_P = 20 m/s)

The tension in a string holding a solid block below thesurface of a liquid  as in shownin the figure is T when the system is at rest.Then what will be the tension in the string if the systemhas upward acceleration a?

An ideal fluid flows in the pipe as shown in the figure, pressure in the fluid at the bottom P₂ is the same as at the top P₁. If the velocity of the top v₁ = 2 m/s. Then the ratio of areas A₁ / A₂ is

A sphere of solid material of specific gravity 8 has aconcentric spherical cavity and just sinks in water. Theratio of radius of cavity to that of outer radius of thesphere must be

A cylindrical container of radius ‘R' and height ‘h’ iscompletely filled with a liquid. Two horizontal L-shapedpipes of small cross-sectional area ‘a’ are connectedto the cylinder as shown in the figure. Now the twopipes are opened and fluid starts coming out of thepipes horizontally in opposite directions. Then thetorque due to ejected liquid on the system is

Figure shows water filled in a symmetrical container,four pistons of equal area A are used at the fouropenings to keep the water in equilibrium. Now anadditional force F is applied at each piston. Theincrease in the pressure at the centre of the containerdue to this addition is

An open tank 10 m long and 2 m deep is filled up to 1.5 m height of oil of specific gravity 0.82. The tank is uniformly accelerated along its length from rest to a speed of 20 m/s horizontally. The shortest time in which the speed may be attained without spilling any oil is a.
 

A U-tube of base length 'l ' filled with the same volumeof two liquids of densities ρ and 2 ρ is moving with anacceleration ‘a’ on the horizontal plane. If the heightdifference between the two surfaces (open toatmosphere) becomes zero, then the height h is givenby

A narrow tube completely filled with a liquid is lying ona series of cylinders as shown in the figure. Assumingno sliding between any surfaces, the value ofacceleration of the cylinders for which liquid will notcome out of the tube from anywhere is given by

The velocity of the liquid coming out of a small hole ofvessel containing two different liquids of densities 2rani r as shown in the figure is

A non-uniform cylinder of mass m, length / and radius ρ is having its centre of mass at a distance 1/4 fromthe centre and lying on the axis of the cylinder. Thecylinder is kept in a liquid of uniform density ρ . Themoment of inertia of the rod about the centre of massis I. The angular acceleration of point A relative to pointB just after the rod is released from the position asshown in the figure is

A square box of water has a small hole located in one of the bottom corners. When the box is full and sitting on a level surface, complete opening of the hole results in a flow of water with a speed v0, as shown in Fig. (a). When the box is still half empty, it is tilted by 45° so that the hole is at the lowest point. Now the water will flow out with a speed of