Properties of matter :: Question Bank for Plus One (Class XI)

1.Distinguish between inter atomic and intermolecular forces.
2.What do you mean by saying, crystalline solids are anisotropic and amorphous solids are isotropic in behavior?
3.Explain, (a) deforming force,(b) elastic body,(c) plastic body (d) elasticity.
4.The length of a metal is l1, when the tension in it is T1 and l2, when the tension is T2. Find the original length of the wire.
5.A wire stretches a certain amount under a load.If the load and diameter are both increased to three times, find the stretch caused in the wire. ( Ans: reduced by three times) .
6.What is more elastic : water or air, Why?
7.What is the value of Young’s modulus for a perfectly rigid body ?
8.How does the young’s modulus change with the rise in temperature?
9.The length of a wire is cut to half. What will be the effect on the increase in it’s length, under a given load?
10.Two wires are made of same material. The length of the first is half that of the second wire and it’s diameter is double that of the second wire. If equal loads are applied on both wires, find the ratio in their lengths. (Ans. 1:8)
11.Which state of matter has volume elasticity?
12.which type of strain is there, when a spiral spring is stretched by a force?
13.A load of 2 kg produces an extension of 1mm in a wire of 3m in length and 1mm in diameter. Calculate the young’s modulus of elasticity of the wire. ( 7.48×1010)
14.What force is required to stretched a wire of steel 1 in cross section to double it’s length ? YSsteel = 2 x 1011 Nm-2. (4 x 107N)
15.A stress of 1kg /sq mm. is applied to a wire of which Young’s modulus is 1011Nm-2. Find the % increase in it’s length. (.0098%)
16.A tank 5 metre high is half filled with water and then filled to the top with oil of density 0.85 g/c.c. What is the pressure at the bottom of the tank due to these liquids? (4.5325 x 104N/m2)
17.A rectangular film of liquid is extended from 5cm x 3cm. If the work done is
3 x 10-4J . Find the surface tension of the liquid. (0.1 N/m)
18.A U tube contains water and methylated spirit separated by mercury. The mercury columns in the two arms are in level with 10.0cm of water in one arm, and 12.5 cm of spirit in the other. What is the relative density of spirit ? (0.8)
19. A piece of wood of relative density 0.25, floats in a pile containing oil of relative density 0.81.What is the percentage of volume of the wood above the surface of the oil? (69.2 %)
20. A piece of pure gold of density 19.3 g/cm3 is suspected to be hollow inside.It weighs 38.865 g in water. Calculate the volume of the hollow portion of
the gold . (2.403 cm3)

21. A cube of wood floating in water supports a 200g mass resting at the centre of its top face. When the mass is removed, the cube raises by 2 cm. Find the volume of the cube. (1000 cm3)
22. A solid floats with ¼ th. Of its volume above the surface of water, calculate the density of the solid. (750 kg/m3)

23. A wire ring of 30.0mm radius resting flat on the surface of the liquid is raised. The pull required is 3.03 gf more, before the film breaks than it is after. Calculate the surface tension of the liquid. (78.76 dyne/cm)

24. Calculate the energy evolved when 8droplets of water (surface tension 0.072N/m) of radius 0.5mm each combined into one. (9.05 x 107 J)

25. Find the work done in blowing a soap bubble of surface tension 0.06 N/m)from 2 cm radius to 5 cm radius. (0.003168 J)
26. Why do a spring balance show wrong measure after long use?
What is the advantage of any hydraulic system?
27. (a) Why does mercury drops its level in a capillary tube?
(b) If you double the radius of the capillary tube what will be the drop in height raise in the tube?
(c) Two liquids of equal mass and different densities ?1, & ?2 are mixed. What is the equivalent density?
28. (a) A balloon filled with helium gas does not rise indefinitely in space. Why?
(b) Why do asbestos roof of buildings get lifted in hurricane?
(c) If the barometric tube is tilted by 300 with the vertical, how much length of mercury column will stand at atmospheric pressure at sea level?
29. What is the ratio of r.m.s speed of oxygen and hydrogen molecules at the same temperature?
What do you mean by anisotropy? Name the solid that shows anisotropy.
What does Hooks law essentially define?
30. (a) What will be the effect of temperature on the angle of contact of a liquid?
(b) When a shaving brush is taken out of water its hair cling together. Why?
(c) Surface tension of all lubricating oils and paints is kept low . Why?
(d) If two row boats happen to sail parallel, and close to each other, they experience a force which pulls them towards each other. Give reason for it ?
31. The diameter of ball A, is twice of that of B. What will be the ratio of their terminal velocities in water?
32 Define—Mean free path, Absolute zero, Mean free path, Coefficient of viscosity, Elastic limit, Elastic fatigue.
33. (a) What is metacentre? How does it determine the equilibrium?
(b) Plot Load Vs Extension curve for a metal on the graph and depicts :-
(i) Yield point, (ii) Breaking point,(iii)Elastic limit(iv) permanent set.
34. Two liquids of specific gravity 1.2 and 0.84 are poured into the limbs of a
U-tube until the difference in levels of their upper surfaces is 9 cm.What will be the heights of their respective surfaces above the common surface in the U-tube? What is the pressure at the common surface? (2520 N/m2 )
35. Two equal drops of water are falling through air with a steady velocity v, If the drops coalesce, What will be the new steady velocity?
36. What are the limitations of Bernaulli’s Theorem?
37. Explain why: (1) To keep a piece of paper horizontal, you should blow over and not under it. (2) It is advised not to stand near a running train.
38. Explain the concept of absolute zero on the basis of kinetic theory of gases.
39.When a wire is stretched by a certain force, its elongation is x. If the second wire of the same material has four times the length, and double the radius, of the first wire, and is stretched by the same force as before, find its elongation. (x)
40.The absolute temperature of the gas is increased 3 times.What will be the increase in root mean velocity of the gas molecules? (0.732C)
41.A spring balance reads 10 Kg when a bucket of water is suspended from it.What is the reading on the spring balance when (1) an ice cube of mass 1.5 kg is put into the bucket; (2) an iron piece of mass 7.8 kg suspended by another string is immerses with half its volume inside the water in the bucket (relative density of iron = 7.8) (11.5kg, 10.5kg)
42. Write the forces experienced by a sphere going down a vertical column of liquid .Giving reason for the terminal velocity, derive an expression for terminal velocity.
43.Prove that the average kinetic energy of a molecule of an ideal gas is directly proportional to the absolute temperature of the gas.
44.State and explain Toricellian theorem.
45.(i) Prove that the work done in stretching a wire = ½ x tension x extension.
(ii) Prove that the work done per unit volume in stretching a wire for every type of strain = ½ x stress x strain.
46. State and prove Bernoulli’s theorem.
47.Derive the expression for pressure of a gas in a container. Using it,relate kinetic energy with pressure.
48.Explain the function of a venturimeter to find velocity of flow of liquid through a tube.
49.what are the factors affecting viscous force in a liquid flowing in a tube? Derive a relation for the velocity up to which the liquid can have streamlined flow.
50. Calculate the percentage increase in the length of a wire of diameter 2.5 mm stretched by a force of 100 kgwt.Young’s modulus of elasticity of the material of the wire is 12.5 x 1011dyne /
51.A cube of aluminum each of side 4cm is subjected to a tangential force. The top face of the cube is sheared through 0.012 cm with respect to the bottom face.
Find (i) shearing strain (ii) shearing stress and the shearing force.
Given:-? =2.08 x 1011 dyne /cm2.( 6.24 x 103dyne/cm2, 9.984 x 109 dyne)
52. A plate of metal rests on a layer of castor oil 2mm thick whose coefficient of viscosity is 15.5 poise. Calculate the horizontal force required to move the plate with a speed of 3 cm/sec. (2350 dyne.)
53. Water flows through a horizontal pipe of varying cross sectional area at the rate of 20 liters per minute. Determine the velocity of water at a point where diameter is 4 cm. (0.2639 m/sec)
54.The cylindrical tube of a spray pump has a cross section of 8.0 cm2 one of which has 40 fine holes each of diameter 1.0mm . If the liquid flow inside the tube is
1.5 m per minute, what is the speed of ejection of the liquid through the holes? (0.637 m/sec)
55. What should be the average velocity of water in a tube of diameter 2.0 cm so that the flow is laminar? The viscosity of water is 0.001 N/m2s.(0.1m/s)
56. At what speed will the velocity of a stream of water be equal to 20cm of mercury column. Taking g=10m/s2. (7.3756m/s)
57.Calculate the total energy per unit mass possessed by water at a point ,where the pressure is 98x103n/m2,velocity is 0.1m/secand height of water level from the ground is 0.20m(g=9.8m/s2) (99.965 J/kg)
58. Water flows through a horizontal pipe of which the cross sectional area is not constant. The pressure is 1cm pf mercury where the velocity is 0,35m/sec.Find the pressure at a point where the velocity is 0.656m/sec.(0.00887mm of Hg.)
59.Find the velocity of efflux of water from an orifice near the bottom of a tank in which the pressure is 4.9x104N/m2 above the atmospheric pressure.(9.893 m/sec)
60.The diameter of a pipe at two points, where a venturimeter is connected,is 8cm and 5cm and the difference of levels in it is 4cm.Calculate the volume of water flowing through the pipe per second.(1889c.c.s-1)
61.Explain why small drops of mercury are spherical and large drops become flat/
62. A razor blade can be made to float on water. What force act on this blade?
63.A shot is obtained by pouring molten lead through narrow holes into water from certain height. The falling lead solidifies and takes the form of small spheres. Explain the phenomenon.
64.Water is depressed in a glass tube whose inner surface is coated with paraffin wax. Why?
65. When bits of camphor are dropped on water,they move helter-skelter.Why?
66.Why does oil spread over the surface of water?
67.Put a piece of chalk into water.The chalk will emit bubbles in all directions. Explain the phenomenon.
68.Why the tip of nib of a pen is split?
69.Why does an iron needle float on clean water but sink when some detergent is added to this water?
70.It is better to wash the clothes in hot soap solution.Why?
71What should be the average velocity of water in a tube of radius 0.005m so that the flow is just turbulent? Viscosity of water is 0.001 Pa-s. (0.2 m/s)
72.What will be the root mean square velocity of helium at 400C, if we know that of oxygen molecules is 460m/s at 00C ?Molecular weight of oxygen is 32g/mole and of helium 4g/mole. (1393.1m/s)
73. A given mass of gas at -730c, exerts a pressure of 50cm of mercury.What pressure will it exert at 270c, if the volume remains constant? (75 cm of Hg)
74.An air bubble of 1.0cm3 rises from the bottom of a lake 40m deep at a temperature of 120c.To what volume does it grow when it reaches the surface, which is at temperature of 350c? Given, 1 atm = 1.01x 105Pa. ( 5.275 X 10-6m3 )
75.Four molecules of a gas have speeds 2,4,6,8 Km/sec respectively. Calculate (1)average and (2) root mean square speed. (5Km/s, 5.48 Km/s)
76.Find the temperature at which root mean square velocity of a gas is half of its value at 00c,pressure remaining constant. (-204.750C)

77.A liquid drop of diameter 4mm break into 1000 droplets of equal size.Calculate the resultant change in the surface energy.
Surface tension of the liquid is 0.07 N/m.(3168 X10-8J)
78 Explain hydrostatic paradox. Illustrate with an example.
79.(a) Why should a field be ploughed before sowing?
(b) Explain why the oil rises in a wick of a lamp?
(c) The antiseptics used for cuts and wounds in human flesh have low surface tension. Explain.
80. Calculate the force required to take away a flat plate of radius 5cm.from the surface of water .Given surface tension of water = 72×10-3N/m. (0.022628 N)
81.Calculate the molecular kinetic energy of 1 gram of helium having molecular weight 4, at 1270C.Given ,R= 8.31J mole-1K-1. (1246.5 J)
82.At what temperature is the root mean square speed of an atom in an argon gas cylinder equal to the r.m.s speed of a helium gas atom at -200C ?(Atomic mass of argon = 39.9, of helium =4.0). (2523.7 K )
82.State the postulates of kinetic theory of gases. Explain the pressure exerted by an ideal gas.
83.From Kinetic Theory of gases , explain kinetic interpretation of temperature and absolute zero.
84. Calculate the temperature at which root mean square velocity of SO2 molecules is the same as that of the O2 molecules at 1270C.Molecular weight of O2 and SO2 are 32 and 64 respectively. (5270C)
85.At what temperature ,pressure remaining constant, the r.m.s velocity of hydrogen be double its value at N.T.P? (8190C)

86. Write the dimensional formula and S.I unit of compressibility. What is poission’s ratio?

87. What will happen to the potential energy of the atoms of a solid, when (1) it is compressed and (2) when it is stretched?

88. If water is used instead of mercury in a barometer, what would be the height of water?

89. When wax is rubbed on cloth, the cloth becomes water proof. Why?

90. At what temperature, the surface tension of a liquid is zero?

91. What is the terminal velocity of a body in a free falling system?

94. What should be the properties of a liquid to satisfy Bernaulli’s theorem?

95. A U shaped wire is dipped in a soap solution and removed. The thin film formed between the wire and a light slider supports a weight of 1.5 x 10-2N. The length of the slider is 30 cms . What is the surface tension of the film? (2.5 x 10-2N/m)
96. The cylindrical tube of a spray pump has a cross section of 8 cm2. one end of which has 40 fine holes each of diameter 1mm. If the liquid flow inside the tube is 1.5m per minute, what is the speed of ejection of the liquid through the holes?(0.637)