ShilpaFlame Institute

10. Two solids A and B float in water. It is observed that A floats with half its volume immersed and B floats with 2/3 of its volume immersed. Compare the densities of A and B

(a) 4 : 3 (b) 2 : 3 (c) 3 : 4 (d) 1 : 3 Answer-c (4)

7. A cubical block is floating in a liquid with half of its volume immersed in the liquid. When the whole system accelerates upwards with acceleration of g/3, the fraction of volume immersed in the liquid will be

(a) 1/2 (b) 3/8 (c) 2/3 (d) 3/4 Answer-a (22)

6. A metallic block of density

5 gm cm–3 and having dimensions 5 cm × 5 cm × 5 cm is weighed in water. Its apparent weight will be (a) 5 × 5 × 5 × 5 gf (b) 4 × 4 × 4 × 4 …

5. A concrete sphere of radius R has a cavity of radius r which is packed with sawdust. The specific gravities of concrete and sawdust are respectively 2.4 and 0.3 for this sphere to float with its entire volume submerged under water. Ratio of mass of concrete to mass of sawdust will be

(a) 8 (b) 4 (c) 3 (d) Zero Answer-b (7)

4. In making an alloy, a substance of specific gravity and mass is mixed with another substance of specific gravity and mass ; then the specific gravity of the alloy is

s1 and mass m1 is mixed with another substance of specific gravity s2 and mass m2 ; then the specific gravity of the alloy is (a) ( m1 + m2 )/(s1 +s2 ) …

3. A hemispherical bowl just floats without sinking in a liquid of density

1.2 × 103kg/m3. If outer diameter and the density of the bowl are 1 m and 2 × 104 kg/m3 respectively, then the inner diameter of the bowl will be (a) 0.94 m (b) 0.97 m (c) 0.98 m …

2. A log of wood of mass 120 Kg floats in water.

The weight that can be put on the raft to make it just sink, should be (density of wood = 600 Kg/m3) (a) 80 Kg (b) 50 Kg (c) 60 Kg …

1. An ice berg of density

900 Kg/m3 is floating in water of density 1000 Kg/m3. The percentage of volume of ice-cube outside the water is (a) 20% (b) 35% (c) 10% …

31. Radius of an air bubble at the bottom of the lake is r and it becomes 2r when the air bubbles rises to the top surface of the lake. If P cm of water be the atmospheric pressure, then the depth of the lake is

(a) 2p (b) 8p (c) 4p (d) 7p Answer-d (19)

29. Why the dam of water reservoir is thick at the bottom

(a) Quantity of water increases with depth (b) Density of water increases with depth (c) Pressure of water increases with depth (d) Temperature of water increases with depth Explanation- (c) A torque is acting on the wall of the dam …

28. A given shaped glass tube having uniform cross section is filled with water and is mounted on

a rotatable shaft as shown in figure. If the tube is rotated with a constant angular velocity ω then (a) Water levels in both sections A and B go up (b) Water level in Section A goes up and that …

26. Three liquids of densities d,2d and 3d are mixed in equal proportions of weights. The relative density of the mixture is

(a) 11d/7 (b) 18d/11 (c) 13d/9 …

19. A vertical U-tube of uniform inner cross section contains mercury in both sides of its arms. A glycerin

(density = 1.3 g/cm3) column of length 10 cm is introduced into one of its arms. Oil of density 0.8 gm/cm3 is poured into the other arm until the upper surfaces of the oil and glycerin are in the same …

18. The height to which a cylindrical vessel be filled with a homogeneous liquid, to make the average force with which the liquid presses the side of the vessel equal to the force exerted by the liquid on the bottom of the vessel, is equal to

(a) Half of the radius of the vessel (b) Radius of the vessel (c) One-fourth of the radius of the vessel (d) Three-fourth of the radius of the vessel Answer-b (9)

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

(a) Increases by 2% (b) Decreases by 2% (c) Remains unchanged (d) Sometimes increases and sometimes decreases Answer-a (8)

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

(a) Zero (b) Equal to 76 cm (c) More than 76 cm (d) Less than 76 cm Answer-d (0)

16. A beaker containing a liquid is kept inside a big closed jar. If the air inside the jar is continuously pumped out, the pressure in the liquid near the bottom of the liquid will

(a) Increases (b) Decreases (c) Remain constant (d) First decrease and then increase Answer-b (3)

17. A barometer tube reads 76 cm of mercury. If the tube is gradually inclined at an angle of 60o with vertical, keeping the open end immersed in the mercury reservoir, the length of the mercury column will be

(a) 152 cm (b) 76 cm (c) 38 cm (d) 38√3 cm Answer-a (2)

21 If two liquids of same masses but densities

ρ1 and ρ2 respectively are mixed, then density of mixture is given by (a) ρ=(ρ1 + ρ2)/2 (b) ρ=(ρ1 + ρ2)/( 2 ρ1 ρ2) (c) …

15. 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

(a) (i) B (ii) D (b) (i) C (ii) D (c) (i) B (ii) C (d) (i) B (ii) A Explanation- (a) Due to acceleration towards right, there will be a pseudo force in a left direction. So the pressure …

6. 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

104. The height of the hill is (a) 250 m (b) 2.5 km (c) 1.25 km (d) 750 m Answer-b …

5. 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 (a) 105 N/m (b) 2 × 105 N/m (c) Zero (d) Infinity Explanation- (c) As the both points are at the surface of liquid and these points …

3. 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)An inverted …

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

(a) 2/3 (b) 4/3 (c) 3/2 (d) 3 Answer-b (3)

11. When a large bubble rises from the bottom of a lake to the surface. Its radius doubles. If atmospheric pressure is equal to that of column of water height H, then the depth of lake is

(a) H (b) 2H (c) 7H (d) 8H Answer-c (5)

12. The volume of an air bubble becomes three times as it rises from the bottom of a lake to its surface. Assuming atmospheric pressure to be 75 cm of Hg and the density of water to be 1/10 of the density of mercury, the depth of the lake is

(a) 5 m (b) 10 m (c) 15 m (d) 20 m Answer-c (24)

10. The pressure at the bottom of a tank containing a liquid does not depend on

(a) Acceleration due to gravity (b) Height of the liquid column (c) Area of the bottom surface (d) Nature of the liquid Answer-c (8)

9. A body of density

d1 is counterpoised by of weights of density d2 in air of density d. Then the true mass of the body is (a) M …

7. Density of ice is

ρ and that of water is σ . What will be the decrease in volume when a mass M of ice melts (a) M/( σ – ρ ) …

4. A uniformly tapering vessel is filled with a liquid of density

900 kg/m3. The force that acts on the base of the vessel due to the liquid is(g=10 m/sec) (a) 3.6 N (b) 7.2 N (c) 9.0 N (d) 14.4 N Answer-b (83)

4. In the above graph, point D indicates

(a) Limiting point (b) Yield point (c) Breaking point (d) None of the above Answer-c (6)

10. The graph is drawn between the applied force F and the strain (x) for a thin uniform wire. The wire behaves as a liquid in the part

(a) ab (b) bc (c) cd (d) oa Explanation- (b) At point b, yielding of material starts. (44)

19. The stress-strain curves for brass, steel and rubber are shown in the figure. The lines A, B and C are for

(a) Rubber, brass and steel respectively (b) Brass, steel and rubber respectively (c) Steel, brass and rubber respectively (d) Steel, rubber and brass respectively Answer-c (7)

18. The points of maximum and minimum attraction in the curve between potential energy (U) and distance (r)of a diatomic molecules are respectively

(a) Sand R (b) T and S (c) R and S (d) S and T Answer-d (25)

14. The diagram shows stress v/s strain curve for the materials A and B. From the curves we infer that

(a) A is brittle but B is ductile (b) A is ductile and B is brittle (c) Both A and B are ductile (d) Both A and B are brittle Explanation-(b) In ductile materials, yield point exist while in …

1. If pressure at half the depth of a lake is equal to 2/3 pressure at the bottom of the lake then what is the depth of the lake

(a) 10 m (b) 20 m (c) 60 m (d) 30 m Answer-b (7)

17. A student plots a graph from his reading on the determination of Young’s modulus of a metal wire but forgets to label. The quantities on X and Y axes may be respectively

(a) Weight hung and length increased (b) Stress applied and length increased (c) Stress applied and strain developed (d) Length increased and weight hung Answer-c (5)

16. The diagram shows the change x in the length of a thin uniform wire caused by the application of stress F at two different temperatures

16. The diagram shows the change x in the length of a thin uniform wire caused by the application of stress F at two different temperatures T1 and T2. The variations shown suggest that (a) T1 > T2 (b) T1 < T2 …

15. Which one of the following is the Young’s modulus (in N/m2) for the wire having the stress-strain curve shown in the figure

(a) 9×1011 (b) 8×1011 (c) 10×1011 (d) 2×1011 Answer-d (6)

12. The potential energy U between two molecules as a function of the distance X between them has been shown in the figure. The two molecules are

(a) Attracted when x lies between A and B and are repelled when X lies between B and C (b) Attracted when x lies between B and C and are repelled when X lies between A and B (c) Attracted …

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