Tiêu đề PROPERTIES OF MATTER & FLUID MECHANICS.pdf ✅

NEET : Physics [ 264 ] www.allendigital.in  Digital D C B A Elongation load 13. A mass of 0.5 kg is suspended from wire, then length of wire increase by 3 mm then find out work done : (1) 4.5 × 10-3 J (2) 7.3 × 10-3 J (3) 9.3 × 10-2 J (4) 2.5 × 10–2 J 14. If the strain in a wire is not more than 1/1000 and Y = 2 × 1011 N/m2, Diameter of wire is 1mm. The maximum weight hung from the wire is:- (1) 110 N (2) 125 N (3) 157 N (4) 168 N 15. When a tension F is applied in uniform wire of length  and radius r, the elongation produced is e. When tension 2F is applied, the elongation produced in another uniform wire of length 2 and radius 2r made of same material is :– (1) 0.5 e (2) 1.0 e (3) 1.5 e (4) 2.0 e 16. How much force is required to produce an increase of 0.2% in the length of a brass wire of diameter 0.6 mm ? [Young's modulus for brass = 0.9 × 1011N/m2] (1) Nearly 17 N (2) Nearly 34 N (3) Nearly 51 N (4) Nearly 68 N 17. If the interatomic spacing in a steel wire is 2.8 × 10–10 m and Ysteel = 2 × 1011 N/m2, then force constant in N/m is – (1) 5.6 (2) 56 (3) 0.56 (4) 560 18. The load versus elongation graph for four wires of the same material and same length is shown in the figure. The thinnest wire is represented by the line. (1) OA (2) OB (3) OC (4) OD 19. The mean distance between the atoms of iron is 3 × 10–10 m and inter atomic force constant for iron is 7 N/m. The young's modulus of elasticity for iron is : (1) 2.33× 105 N/m2 (2) 23.3 × 1010 N/m2 (3) 233 × 1010 N/m2 (4) 2.33 × 1010 N/m2 20. Cross section area of a steel wire (Y=2.0 × 1011 N/m2) is 0.1 cm2. The required force, to make its length double will be – (1) 2 × 1012N (2) 2 × 1011N (3) 2 × 1010N (4) 2 × 106N 21. For a given material, the Young's modulus is 2.4 times that of rigidity modulus. Its Poisson's ratio is : (1) 2.4 (2) 1.2 (3) 0.4 (4) 0.2 22. The diameter of a brass rod is 4 mm and Young's modulus of brass is 9 × 1010 N/m2. The force required to stretch by 0.1% of its length is : (1) 360 N (2) 36 N (3) 144 × 103 N (4) 36 × 105 N 23. Poisson's ratio can not have the value : (1) 0.1 (2) 0.7 (3) 0.2 (4) 0.5 24. Two wires of the same length and material but different radii r1 and r2 are suspended from a rigid support both carry the same load at the lower end. The ratio of the stress developed in the second wire to that developed in the first wire is – (1) 1 2 r r (2) 2 1 2 2 r r (3) 5 2 1 2 r r       (4) 1 2 1 2 r r       25. An increases in pressure required to decreases the 200 litres volume of a liquid by 0.004% in container is : (Bulk modulus of the liquid = 2100 MPa) (1) 188 kPa (2) 8.4 kPa (3) 18.8 kPa (4) 84 kPa 26. If 'S' is stress and 'Y' is Young's modulus of material of a wire, the energy stored in the wire per unit volume is (1) S 2Y (2) 2 2Y S (3) 2 S 2Y (4) 2S2Y 27. For a constant hydraulic stress on an object, the fractional change in the object's volume V V        and its bulk modulus (B) are related as : (1) V B V   (2) V 1 V B   (3) V 2 B V   (4) V 2 B V  − 
Properties of Matter and Fluid Mechanics  Digital www.allendigital.in [ 265 ] 28. A wire of length L and cross-sectional area A is made of a material of Young's modulus Y. The work done in stretching the wire by an amount x is given by :- (1) 2 YAx L (2) 2 YAx 2L (3) 2 YAL x (4) 2 YAL 2x FLUIDS STATICS 29. Two vessels A and B have the same base area and contain water to the same height, but the mass of water in A is four times that in B. The ratio of the liquid thrust at the base of A to that at the base of B is :-   H A B (1) 4 : 1 (2) 2 : 1 (3) 1 : 1 (4) 16 : 1 30. A cylinder is filled with a liquid of density d upto a height h. If the beaker is at rest, then the mean pressure on the wall is :- (1) Zero (2) hdg (3) h dg 2 (4) 2 hdg 31. The spring balance A read 2 kg. with a block m suspended from it. A balance B reads 5 kg. when a beaker with liquid is put on the pan of the balance. The two balances are now so arranged that the hanging mass is inside the liquid in the beaker as shown in fig. In this situation :– (1) The balance A will read more than 2 kg. (2) The balance B will read more than 5 kg. (3) The balance A will read less than 2 kg. and B will read more than 5 kg. (4) The balance A and B will read 2 kg. and 5 kg. respectively. 32. A jar is filled with two non-mixing liquids 1 and 2 having densities and, respectively. A solid ball, made of a material of density 3, is dropped in the jar. It comes to equilibrium in the position shown in the figure. Which of the following is true for 1, 2 & 3 (1) 3 < 1 < 2 (2) 1 > 3 > 2 (3) 1 < 2 < 3 (4) 1 < 3 < 2 33. A boat having a length of 3 metre and breadth 2 metre is floating on a lake. The boat sinks by one cm when a man gets on it. The mass of the man is (1) 60 kg (2) 62 kg (3) 72 kg (4) 128 kg 34. If the density of a block is 981 kg/m3 then it shall (1) Sink in water (2) float with some part emmersed in water (3) float completely immersed in water (4) float completely out of water. 35. A wooden block, with a coin placed on its top, floats in water as shown in figure. The distance  and h are shown there. After sometime the coin falls into the water. Then :– (1)  decreases and h increases (2)  increases and h decreases (3) both  and h increase (4) both  and h decrease B A m Liquid 1 Liquid 2 1 1 3 h  coin
NEET : Physics [ 266 ] www.allendigital.in  Digital 36. A piece of ice is floating in a jar containing water. When the ice melts, then the level of water :- (1) Rises (2) Falls (3) Remains unchanged (4) Changes erratically 37. A sample of metal weights 210 gram in air, 180 gram in water and 120 gram in an unknown liquid. Then :- (1) the density of metal is 3 g/cm3 (2) the density of metal is 7 g/cm3 (3) density of metal is 4 times the density of the unknown liquid (4) the metal will float in water 38. 'Torr' is the unit of :- (1) Pressure (2) Density (3) Volume (4) Flux 39. A sphere is floating in water its 1/3rd part is outside the water and when sphere is floating in unknown liquid, its 3 4 th part is outside the liquid then density of liquid is (1) 4/9 gm/c.c. (2) 9/4 gm/c.c. (3) 8/3 gm/c.c. (4) 3/8 gm/c.c. 40. Which of the following works on Pascal's law ? (1) Sprayer (2) Venturimeter (3) Hydraulic lift (4) Aneroid barometer 41. An object of weight W and density is submerged in a fluid of density. Its appearent weight will be (1) W 1 ( ) − (2) 1 ( ) W  −  (3) W 1 1     −    (4) W( )  − 1 42. Which law states that the magnitude of pressure within fluid is equal in all parts ? (1) Pascal's law (2) Gay-Lusac's law (3) Dalton's law (4) Boyle's law 43. A body measures 5 N in air and 2 N when put in water. The buoyant force is (1) 7 N (2) 9 N (3) 3 N (4) None of these 44. Hydraulic press is based upon (1) Archimede's principle (2) Bernoulli's theorem (3) Pascal's law (4) Reynold's number 45. A wooden block is taken to the bottom of a lake of water and then released. it rise up with a (1) Constant acceleration (2) Decreasing acceleration (3) Constant velocity (4) Decreasing velocity FLUIDS DYNAMICS 46. Two water pipes P and Q having diameter 2 × 10–2 m and 4 × 10–2 m respectively are joined in series with the main supply line of water. The velocity of water flowing in pipe P is (1) 4 times that of Q (2) 2 times that of Q (3) 1 2 times that of Q (4) 1 4 times that of Q 47. The cylindrical tube of a spray pump has a radius R, one end of which has n fine holes, each of radius r. If the speed of flow of the liquid in the tube is v, the speed of ejection of the liquid through the hole is :- (1) v R n r       (2) 1 2 v R n r       (3) 3 2 v R n r       (4) 2 v R n r       48. Water from a tap emerges vertically downwards with an initial speed of 1.0 m/s. The cross–sectional area of tap is 10–4 m2. Assume that the pressure is constant throughout the stream of water and that the flow is steady, the cross–sectional area of stream 0.15 m below the tap is :– (1) 5.0 × 10–4 m2 (2) 1.0 × 10–4 m2 (3) 5.0 × 10–5 m2 (4) 2.0 × 10–5 m2