Physics - Mechanical Properties Fluids - Quiz-1

A closed rectangular tank is completely filled with water and is accelerated horizontally with an acceleration a towards right. Pressure is (i) maximum at, and (ii) minimum at

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(i) B (ii) D
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(i) C (ii) D
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(i) B (ii) C
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(i) B (ii) A

8000 identical water drops are combined to form a big drop. Then the ratio of the final surface energy to the initial surface energy of all the drops together is

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1 : 10
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1 : 15
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1 : 20
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1 : 25

Water flows through a frictionless duct with a cross-section varying as shown in the figure. Pressure p at points along the axis is represented by

A body of density $d_{1}$ is counterpoised by Mg of weights of density $d_{2}$ in air of density d. Then the true mass of the body is

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M
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$M (1 - \frac{d}{d_{2}})$
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$M (1 - \frac{d}{d_{1}})$
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$\frac{M (1 - d / d_{2})}{(1 - d / d_{1})}$

A tube of length L is filled completely with an incompressible liquid of mass M and closed at both ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity $ω$ . The force exerted by liquid at the other end is

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$\frac{{Mω}^{2} L}{2}$
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${MLω}^{2}$
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$\frac{{Mω}^{2} L}{4}$
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$\frac{M L^{2} ω^{2}}{2}$

The radius of a soap bubble is increased from R to 2 R. Work done in this process (T = surface tension) is:

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$24 {πR}^{2} T$
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$48 {πR}^{2} T$
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$12 {πR}^{2} T$
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$36 {πR}^{2} T$

The flow rate from a tap of diameter 1.25 cm is 3 lit/min. The coefficient of viscosity of water is $10^{- 3}$ Pas. The nature of flow is :

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Turbulent
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Laminar
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Neither laminar nor turbulent
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data inadequate

A small spherical solid ball is dropped in a viscous liquid. Its journey in the liquid is best described in the figure by :

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Curve A
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Curve B
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Curve C
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Curve D

The value of g at a place decreases by 2%. The barometric height of mercury

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Increases by 2%
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Decreases by 2%
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Remains unchanged
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Sometimes increases and sometimes decreases

The area of cross-section of the wider tube shown in the figure is $800 {cm}^{2} .$ If a mass of 12 kg is placed on the massless piston, then the difference in heights h of the levels of water in the two tubes will be:

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10 cm
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6 cm
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15 cm
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2 cm

Equation of continuity based on :

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Conservation of mass
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Conservation of energy
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Conservation of angular momentum
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None of these

The cylindrical tube of a spray pump has radius R, one end of which has n fine holes, each of radius r. If the speed of the liquid in the tube is v, the speed of the ejection of the liquid through the holes is

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$\frac{{vR}^{2}}{n^{2} r^{2}}$
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$\frac{{vR}^{2}}{{nr}^{2}}$
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$\frac{{vr}^{2}}{n^{2} R^{2}}$
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$\frac{v^{2} R}{nr}$

The weight of an aeroplane flying in the air is balanced by

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Vertical component of the thrust created by air currents striking the lower surface of the wings
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Force due to reaction of gases ejected by the revolving propeller
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Upthrust of the air which will be equal to the weight of the air having the same volume as the plane
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Force due to the pressure difference between the upper and lower surfaces of the wings created by different air speeds on the surfaces

If there were a smaller gravitational effect, which of the following forces do you think would alter in some respect?

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Viscous forces
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Archimedes uplift
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Electrostatic force
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None of the above

A U tube with both ends open to the atmosphere,is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see diagram). The density of the oil is

(a) $650 k g m^{- 3}$

(b) $425 k g m^{- 3}$

(d) $928 k g m^{- 3}$

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3
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4
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1
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2

Three liquids of densities $ρ_{1}, ρ_{2} a n d ρ_{3}$ (with $ρ_{1} > ρ_{2} > ρ_{3}$ ), having the same value of surface tension T, rise to the same height in three identical capillaries. The angles of contact $θ_{1}, θ_{2} a n d θ_{3}$ obey

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$\frac{π}{2} > θ_{1} > θ_{2} > θ_{3} \geq 0$
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$0 \leq θ_{1} < θ_{2} < θ_{3} < \frac{π}{2}$
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$\frac{π}{2} < θ_{1} < θ_{2} < θ_{3} < π$
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$π > θ_{1} > θ_{2} > θ_{3} > \frac{π}{2}$

Two non-mixing liquids of densities $ρ$ and n $ρ$ (n>1) are put in a container. The height of each liquid is h. A solid cylinder floats with its axis vertical and length pL $(p < 1)$ in the denser liquid. The density of the cylinder is d. The density d is equal to:

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{2+(n+1)p} $ρ$
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{2+(n-1)p} $ρ$
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{1+(n-1)p} $ρ$
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{1+(n+1)p} $ρ$

The approximate depth of an ocean is 2700 m. The compressibility of water is 45.4 x 10^-11 Pa^-1 and density of water is 10³kg/m³. What fractional compression of water will be obtained at the bottom of the ocean?

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0.8x10^-2
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1.0x10^-2
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1.2x10^-2
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1.4x10^-2

A wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250 m². Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be (P_air=1.2kg/m³)

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4.8x10⁵N, downwards
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4.8x10⁵N, upwards
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2.4x10⁵N, upwards
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2/4x10⁵N, downwards

The cylindrical tube of a spray pump has radius R, one end of which has n fine holes, each of radius r. If the speed of the liquid in the tube is v, then the speed of ejection of the liquid through the holes will be:

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vR²/n²r²
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vR²/nr²
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vR²/n³r²
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v²R/nr

The heart of a man pumps 5L of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury is $13.6\times 10^3$kg/m³ and g =10 m/s², then the power of heart in watt is:

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1.70
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2.35
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3.0
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1.50

Water rises to a height h in capillary tube . If the length of capillary tube above the surface of water is made less than h, then

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water rises upto the tip of capillary tube and then starts overflowing like a fountain
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water rises upto the top of capillary tube and stays there without overflowing
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water rises upto a point a little below the top and stays there
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water does not rise at all

A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then:

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$E n e r g y = 4 V T (\frac{1}{r} - \frac{1}{R}) i s r e l e a s e d$
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$E n e r g y = 3 V T (\frac{1}{r} + \frac{1}{R}) i s r e l e a s e d$
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$E n e r g y = 3 V T (\frac{1}{r} - \frac{1}{R}) i s r e l e a s e d$
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$E n e r g y is n e i t h e r r e l e a s e d n o r a b s o r b e d$

An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?

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$\frac{1}{2} m v^{3}$
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$m v^{3}$
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$\frac{1}{2} m v^{2}$
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$\frac{1}{2} m^{2} v^{2}$

Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is 36 g and its density is 9 g / cm³. If the mass of the other is 48 g, its density in g / cm³ will be:

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$\frac{4}{3}$
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$\frac{3}{2}$
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3
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5

An inverted bell lying at the bottom of a lake 47.6 m deep has 50 cm³ of air trapped in it. The bell is brought to the surface of the lake. The volume of the trapped air will be (atmospheric pressure = 70 cm of Hg and density of Hg = 13.6 g/cm³)

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350 cm³
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300 cm³
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250 cm³
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22 cm³

A siphon in use is demonstrated in the following figure. The density of the liquid flowing in siphon is 1.5 gm/cc. The pressure difference between the point P and S will be

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$10^{5} N / m$
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$2 \times 10^{5} N / m$
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Zero
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Infinity

The height of a mercury barometer is 75 cm at sea level and 50 cm at the top of a hill. Ratio of density of mercury to that of air is $10^{4}$ . The height of the hill is

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250 m
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2.5 km
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1.25 km
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750 m

Equal masses of water and a liquid of relative density 2 are mixed together, then the mixture has a density of

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2/3
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4/3
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3/2
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3

A barometer kept in a stationary elevator reads 76 cm. If the elevator starts accelerating up, the reading will be

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Zero
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Equal to 76 cm
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More than 76 cm
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Less than 76 cm

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Practice Physics Quiz Questions and Answers

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Practice Physics Quiz Questions and Answers

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