1. The property of a liquid by virtue of which it opposes relative motion between its layers is called
A) Viscosity
B) Elasticity
C) Density
D) Pressure
Answer: A) Viscosity
Explanation: Viscosity measures internal friction between moving layers of fluid.
2. The force of friction between adjacent layers of a liquid in motion is called
A) Viscous force
B) Cohesive force
C) Adhesive force
D) Surface tension
Answer: A) Viscous force
3. Viscosity is a property of
A) Liquids and gases
B) Solids only
C) Gases only
D) Plasma only
Answer: A) Liquids and gases
4. Viscosity is due to
A) Cohesive forces between molecules
B) Adhesive forces
C) Friction
D) Gravity
Answer: A) Cohesive forces between molecules
5. The SI unit of viscosity is
A) Pascal second
B) Newton
C) Joule
D) Pascal
Answer: A) Pascal second
6. The viscosity of a liquid depends on
A) Nature of liquid
B) Temperature
C) Pressure
D) All of these
Answer: D) All of these
7. When temperature increases, the viscosity of liquids
A) Decreases
B) Increases
C) Remains constant
D) Becomes zero
Answer: A) Decreases
Explanation: Heat weakens cohesive forces in liquids, making them flow easily.
8. When temperature increases, the viscosity of gases
A) Increases
B) Decreases
C) Remains same
D) Becomes zero
Answer: A) Increases
Explanation: Higher temperature increases molecular collisions in gases, increasing resistance to flow.
9. The viscosity of honey is
A) Greater than water
B) Less than water
C) Equal to water
D) Same as oil
Answer: A) Greater than water
Explanation: Honey flows slowly due to higher internal friction.
10. The viscosity of air is
A) Very small
B) Very large
C) Equal to oil
D) Same as water
Answer: A) Very small
11. A liquid having more viscosity flows
A) Slowly
B) Fast
C) With same speed
D) Irregularly
Answer: A) Slowly
12. The viscosity of a perfect fluid is
A) Zero
B) Infinite
C) High
D) Constant
Answer: A) Zero
13. Viscosity is also called
A) Internal friction
B) External pressure
C) Surface tension
D) Kinetic energy
Answer: A) Internal friction
14. The instrument used to measure viscosity is called
A) Viscometer
B) Barometer
C) Manometer
D) Thermometer
Answer: A) Viscometer
15. The viscosity of water is maximum at
A) Low temperature
B) High temperature
C) Freezing point
D) Boiling point
Answer: A) Low temperature
16. The viscosity of liquids is mainly due to
A) Cohesive forces
B) Adhesive forces
C) Air pressure
D) Temperature
Answer: A) Cohesive forces
17. The viscosity of gases is mainly due to
A) Molecular collisions
B) Cohesive forces
C) Density
D) Pressure
Answer: A) Molecular collisions
18. The flow of liquid layers sliding over each other is called
A) Laminar flow
B) Turbulent flow
C) Irregular flow
D) Chaotic flow
Answer: A) Laminar flow
19. When the motion of fluid particles is disorderly, it is called
A) Turbulent flow
B) Laminar flow
C) Streamline flow
D) Uniform flow
Answer: A) Turbulent flow
20. The point beyond which laminar flow changes to turbulent flow is called
A) Critical velocity
B) Terminal velocity
C) Average speed
D) Streamline point
Answer: A) Critical velocity
21. The viscosity of glycerin is
A) Very high
B) Very low
C) Equal to water
D) Same as oil
Answer: A) Very high
22. The viscosity of oils is generally
A) High
B) Low
C) Same as water
D) Zero
Answer: A) High
23. The slow motion of a small sphere through a viscous medium is called
A) Stokes’ motion
B) Free fall
C) Elastic motion
D) Inertial motion
Answer: A) Stokes’ motion
24. The velocity at which viscous force balances weight is called
A) Terminal velocity
B) Average velocity
C) Critical velocity
D) Uniform velocity
Answer: A) Terminal velocity
25. The higher the viscosity, the ______ the flow.
A) Slower
B) Faster
C) Constant
D) Chaotic
Answer: A) Slower
26. Which of the following liquids has least viscosity?
A) Alcohol
B) Glycerin
C) Water
D) Honey
Answer: A) Alcohol
27. The viscosity of air increases with
A) Increase in temperature
B) Decrease in temperature
C) Pressure
D) Volume
Answer: A) Increase in temperature
28. The viscosity of gases decreases with
A) Cooling
B) Heating
C) Compression
D) Motion
Answer: A) Cooling
29. The motion of smoke in air is an example of
A) Turbulent flow
B) Laminar flow
C) Random flow
D) Elastic flow
Answer: A) Turbulent flow
30. The flow of oil in a narrow tube is
A) Laminar
B) Turbulent
C) Uniform
D) Random
Answer: A) Laminar
31. Viscosity is greater in
A) Thick fluids
B) Thin fluids
C) Air
D) Steam
Answer: A) Thick fluids
32. The flow of blood in narrow capillaries is affected by
A) Viscosity
B) Density
C) Pressure
D) Surface tension
Answer: A) Viscosity
33. Viscosity causes
A) Loss of mechanical energy in liquids
B) Gain of energy
C) Increase in density
D) None
Answer: A) Loss of mechanical energy in liquids
34. The study of viscosity is important in
A) Lubrication design
B) Pipeline flow
C) Blood flow studies
D) All of these
Answer: D) All of these
35. Liquids with low viscosity are called
A) Thin liquids
B) Thick liquids
C) Heavy liquids
D) Dense liquids
Answer: A) Thin liquids
36. Viscosity provides resistance to
A) Relative motion between layers
B) Gravity
C) Cohesion
D) Adhesion
Answer: A) Relative motion between layers
37. The term “viscous drag” refers to
A) Resistance due to viscosity
B) Pull due to gravity
C) Force due to magnetism
D) Air pressure difference
Answer: A) Resistance due to viscosity
38. Oil used in machines acts as
A) Lubricant
B) Solvent
C) Coolant
D) Adhesive
Answer: A) Lubricant
39. The function of a lubricant is to
A) Reduce friction
B) Increase friction
C) Cool the machine
D) Absorb shock
Answer: A) Reduce friction
40. The viscosity of a lubricant should be
A) Optimum
B) Very high
C) Very low
D) Zero
Answer: A) Optimum
Explanation: Too high causes resistance; too low causes wear and tear.
41. A fluid having zero viscosity is called
A) Ideal fluid
B) Real fluid
C) Compressible fluid
D) Incompressible fluid
Answer: A) Ideal fluid
Explanation: Ideal fluids are imaginary fluids assumed to have no internal friction.
42. For real fluids, viscosity is always
A) Greater than zero
B) Equal to zero
C) Negative
D) Infinite
Answer: A) Greater than zero
43. The unit of viscosity is the same as that of
A) Stress × Time
B) Pressure × Time
C) Energy
D) Force
Answer: B) Pressure × Time
Explanation: Because viscosity measures the time-dependent resistance to flow.
44. When a liquid flows steadily in parallel layers, each layer slides over the next. This motion is called
A) Laminar flow
B) Turbulent flow
C) Irregular motion
D) Wave motion
Answer: A) Laminar flow
45. The flow of blood in veins is generally
A) Laminar
B) Turbulent
C) Irregular
D) Rotational
Answer: A) Laminar
Explanation: In normal conditions, blood flows in smooth layers in veins.
46. The flow of river water during floods is
A) Turbulent
B) Laminar
C) Smooth
D) Uniform
Answer: A) Turbulent
47. The flow of oil through a narrow pipe is
A) Laminar
B) Turbulent
C) Random
D) Chaotic
Answer: A) Laminar
48. The flow of air around an aircraft is
A) Turbulent
B) Laminar
C) Irregular
D) Rotational
Answer: A) Turbulent
Explanation: Air currents are irregular due to speed and pressure differences.
49. The resistance to motion in fluids is due to
A) Viscosity
B) Density
C) Temperature
D) Pressure
Answer: A) Viscosity
50. A highly viscous fluid will have
A) Strong internal friction
B) Weak internal friction
C) No internal friction
D) Random motion
Answer: A) Strong internal friction
51. The viscosity of thick engine oil compared to water is
A) Much greater
B) Less
C) Same
D) Equal
Answer: A) Much greater
52. Viscosity causes energy loss in
A) Fluid flow
B) Elastic collision
C) Heat transfer
D) Light reflection
Answer: A) Fluid flow
53. The temperature at which viscosity of a liquid is measured is usually
A) Room temperature
B) Freezing temperature
C) Boiling temperature
D) Critical temperature
Answer: A) Room temperature
54. The layer of liquid in contact with solid boundary has
A) Zero velocity
B) Maximum velocity
C) Random velocity
D) Constant velocity
Answer: A) Zero velocity
Explanation: Due to adhesion, the liquid layer sticks to the solid surface.
55. The flow of ink in a pen is controlled by
A) Viscosity
B) Capillarity
C) Density
D) Elasticity
Answer: A) Viscosity
56. Which of the following liquids has the highest viscosity?
A) Honey
B) Oil
C) Water
D) Alcohol
Answer: A) Honey
57. Which of the following has the lowest viscosity?
A) Air
B) Water
C) Kerosene
D) Alcohol
Answer: A) Air
58. The viscosity of gases arises mainly due to
A) Momentum transfer between molecules
B) Density
C) Pressure
D) Cohesion
Answer: A) Momentum transfer between molecules
59. Liquids which flow easily are said to be
A) Less viscous
B) Highly viscous
C) Non-viscous
D) Ideal
Answer: A) Less viscous
60. Honey flows slowly because
A) It has high viscosity
B) It is dense
C) It is sticky
D) It has low temperature
Answer: A) It has high viscosity
61. The viscosity of motor oil is important because it
A) Determines friction in engine parts
B) Controls color of oil
C) Affects fuel consumption
D) Changes density
Answer: A) Determines friction in engine parts
62. If viscosity is too high in a lubricant, it will
A) Cause resistance and heat
B) Improve speed
C) Decrease power
D) Make oil lighter
Answer: A) Cause resistance and heat
63. The viscosity of water is greater at
A) Low temperature
B) High temperature
C) Boiling point
D) Constant pressure
Answer: A) Low temperature
64. The viscosity of air is greater at
A) High temperature
B) Low temperature
C) Constant pressure
D) Room temperature
Answer: A) High temperature
65. The effect of temperature on viscosity is
A) Opposite for liquids and gases
B) Same for both
C) Irregular
D) Negligible
Answer: A) Opposite for liquids and gases
66. The unit of viscosity is the same as
A) Stress × Time
B) Force × Time
C) Pressure × Time
D) Density × Velocity
Answer: C) Pressure × Time
67. The term “viscous drag” refers to
A) Retarding force due to viscosity
B) Pulling force
C) Buoyant force
D) Pressure difference
Answer: A) Retarding force due to viscosity
68. The terminal velocity of a body in a fluid depends on
A) Viscosity of fluid
B) Density of fluid
C) Size of body
D) All of these
Answer: D) All of these
69. The upward force acting on a body falling in a viscous fluid is
A) Viscous drag
B) Buoyant force
C) Friction
D) Surface tension
Answer: A) Viscous drag
70. At terminal velocity, a falling object
A) Falls with constant speed
B) Speeds up continuously
C) Stops moving
D) Falls with uniform acceleration
Answer: A) Falls with constant speed
71. A sphere falls slowly in honey because
A) Honey has large viscosity
B) Honey is dense
C) Honey is sticky
D) Air bubbles stop motion
Answer: A) Honey has large viscosity
72. The viscosity of water is affected by
A) Impurities and temperature
B) Color of water
C) Shape of container
D) Atmospheric pressure
Answer: A) Impurities and temperature
73. The force responsible for slowing down a moving ship in water is
A) Viscous drag
B) Buoyant force
C) Surface tension
D) Inertia
Answer: A) Viscous drag
74. The flow of tar is an example of
A) Very high viscosity
B) Very low viscosity
C) Zero viscosity
D) Ideal flow
Answer: A) Very high viscosity
75. The flow of gas through a narrow tube is
A) Viscous flow
B) Turbulent flow
C) Random flow
D) Ideal flow
Answer: A) Viscous flow
76. Oil spreads more easily on a surface when its viscosity is
A) Low
B) High
C) Constant
D) Zero
Answer: A) Low
77. The flow of lava during volcanic eruption is affected by
A) Viscosity of molten rock
B) Temperature of air
C) Density of ground
D) Gravity
Answer: A) Viscosity of molten rock
78. Syrup flows slowly compared to water because
A) Syrup is more viscous
B) Syrup is dense
C) Syrup is sticky
D) Syrup is cold
Answer: A) Syrup is more viscous
79. Viscosity helps to explain
A) Resistance in fluid motion
B) Diffusion of gases
C) Thermal conduction
D) Light reflection
Answer: A) Resistance in fluid motion
80. The viscosity of air at room temperature is
A) Very low
B) Very high
C) Equal to that of water
D) Zero
Answer: A) Very low
81. Viscosity is greater in
A) Syrup
B) Alcohol
C) Petrol
D) Water
Answer: A) Syrup
82. A lubricant should have
A) Moderate viscosity
B) Very high viscosity
C) Very low viscosity
D) Constant viscosity
Answer: A) Moderate viscosity
83. When temperature increases, viscosity of oil
A) Decreases
B) Increases
C) Remains same
D) Doubles
Answer: A) Decreases
84. When a ball falls through air, it eventually attains
A) Terminal velocity
B) Zero velocity
C) Acceleration
D) Infinite velocity
Answer: A) Terminal velocity
85. The study of viscosity helps in designing
A) Pipelines
B) Engines
C) Chemical plants
D) All of these
Answer: D) All of these
86. Viscosity of gases depends more on
A) Temperature
B) Pressure
C) Color
D) Volume
Answer: A) Temperature
87. The viscosity of water is least at
A) High temperature
B) Low temperature
C) Room temperature
D) Freezing point
Answer: A) High temperature
88. The resistance experienced by a ship moving in water is mainly due to
A) Viscosity of water
B) Density of water
C) Buoyancy
D) Surface tension
Answer: A) Viscosity of water
89. Viscosity opposes
A) Relative motion between fluid layers
B) Gravity
C) Heat
D) Friction
Answer: A) Relative motion between fluid layers
90. The drag on a moving vehicle in air is mainly due to
A) Air viscosity
B) Air density
C) Friction of road
D) Humidity
Answer: A) Air viscosity
91. The flow of paint from a brush depends on
A) Viscosity
B) Density
C) Surface tension
D) Pressure
Answer: A) Viscosity
92. The viscosity of liquids is greater than gases because
A) Liquids have stronger cohesive forces
B) Liquids are less dense
C) Gases are heavier
D) Liquids have weak adhesion
Answer: A) Liquids have stronger cohesive forces
93. The opposite of viscosity is
A) Fluidity
B) Density
C) Elasticity
D) Friction
Answer: A) Fluidity
Explanation: Fluidity means ease of flow; it is the reciprocal of viscosity.
94. The viscosity of tar compared to water is
A) Extremely high
B) Equal
C) Zero
D) Low
Answer: A) Extremely high
95. The viscosity of gases increases with temperature because
A) Molecules collide more often
B) Density decreases
C) Cohesion increases
D) Pressure drops
Answer: A) Molecules collide more often
96. The property that helps the motion of rain through air is
A) Low viscosity of air
B) High density of air
C) Elasticity of air
D) Surface tension
Answer: A) Low viscosity of air
97. The viscosity of mercury compared to water is
A) Higher
B) Lower
C) Equal
D) Zero
Answer: A) Higher
98. The motion of clouds in air shows
A) Turbulent flow
B) Laminar flow
C) Random flow
D) Elastic flow
Answer: A) Turbulent flow
99. The property that causes a raindrop to fall slowly in air is
A) Viscosity of air
B) Surface tension
C) Density
D) Capillarity
Answer: A) Viscosity of air
100. Viscosity is most useful in
A) Designing lubricants and predicting fluid flow
B) Making magnets
C) Producing electricity
D) Mixing chemicals
Answer: A) Designing lubricants and predicting fluid flow