Q.1 Which property of a liquid is responsible for the spherical shape of small liquid drops?
Viscosity
Surface tension
Capillarity
Elasticity
Explanation - Surface tension minimizes the surface area of a liquid, leading small drops to acquire a spherical shape.
Correct answer is: Surface tension
Q.2 The SI unit of pressure is:
Dyne/cm²
Pascal
N/m
Joule
Explanation - Pressure is defined as force per unit area, with SI unit Newton/m², called Pascal.
Correct answer is: Pascal
Q.3 The bulk modulus of a material is defined as:
Stress/Strain
Volume stress/Volumetric strain
Shear stress/Shear strain
Young's modulus × Poisson's ratio
Explanation - Bulk modulus measures resistance to uniform compression, hence it is the ratio of volume stress to volumetric strain.
Correct answer is: Volume stress/Volumetric strain
Q.4 Viscosity of a liquid generally:
Increases with temperature
Decreases with temperature
Remains constant
Becomes zero at high temperatures
Explanation - As temperature increases, intermolecular forces weaken, reducing viscosity in liquids.
Correct answer is: Decreases with temperature
Q.5 The rise of liquid in a capillary tube is due to:
Viscosity
Elasticity
Cohesion and adhesion
Density
Explanation - Capillary action is caused by adhesive forces between liquid and tube walls, and cohesive forces within the liquid.
Correct answer is: Cohesion and adhesion
Q.6 A soap bubble is spherical because:
Air pressure inside is uniform
Gravity is negligible
Surface tension tends to minimize surface area
Viscosity dominates
Explanation - Surface tension pulls the film into a shape with minimum area, which is a sphere.
Correct answer is: Surface tension tends to minimize surface area
Q.7 If a liquid wets a surface, the angle of contact is:
90°
Greater than 90°
Less than 90°
Exactly 180°
Explanation - Liquids that wet surfaces (like water on glass) have acute angles of contact (< 90°).
Correct answer is: Less than 90°
Q.8 Stoke’s law is applicable to:
Motion of projectiles
Flow of gases
Small spherical bodies moving in viscous fluid
Elastic solids
Explanation - Stoke's law gives the viscous force acting on small spherical particles moving through a viscous fluid.
Correct answer is: Small spherical bodies moving in viscous fluid
Q.9 Which has the highest bulk modulus?
Air
Water
Steel
Rubber
Explanation - Steel resists volume change strongly, thus has a very high bulk modulus compared to liquids and gases.
Correct answer is: Steel
Q.10 The dimensions of viscosity are:
[M L⁻¹ T⁻¹]
[M L⁻¹ T⁻²]
[M L⁻² T⁻¹]
[M⁻¹ L T]
Explanation - Viscosity has units of Newton-second per square meter, giving dimensional formula [M L⁻¹ T⁻¹].
Correct answer is: [M L⁻¹ T⁻¹]
Q.11 Excess pressure inside a soap bubble of radius r and surface tension T is:
2T/r
4T/r
T/r
8T/r
Explanation - For soap bubbles, there are two liquid surfaces. Hence excess pressure = 4T/r.
Correct answer is: 4T/r
Q.12 The terminal velocity of a spherical body moving through a viscous fluid is directly proportional to:
Square of radius
First power of radius
Cube of radius
Inversely proportional to radius
Explanation - From Stoke's law, terminal velocity v ∝ r² for a spherical body in viscous fluid.
Correct answer is: Square of radius
Q.13 The property of a body to regain its shape after deformation is called:
Plasticity
Elasticity
Viscosity
Rigidity
Explanation - Elasticity is the ability of a body to regain its original shape when deforming forces are removed.
Correct answer is: Elasticity
Q.14 Hooke’s law states that:
Stress ∝ Strain within elastic limit
Stress = Constant always
Stress ∝ (Strain)²
Strain ∝ Elastic limit
Explanation - Hooke’s law holds for small deformations within the elastic limit where stress is directly proportional to strain.
Correct answer is: Stress ∝ Strain within elastic limit
Q.15 A highly viscous liquid flows:
Fast
Slow
At sonic velocity
Without friction
Explanation - Viscosity resists flow; higher viscosity results in slower flow.
Correct answer is: Slow
Q.16 For a perfectly non-wetting liquid, the angle of contact is:
0°
45°
90°
180°
Explanation - Non-wetting liquids form convex meniscus and have angle of contact = 180°.
Correct answer is: 180°
Q.17 Which among these has the lowest density?
Ice
Mercury
Air
Wood
Explanation - Air is gaseous and much less dense than solids or liquids.
Correct answer is: Air
Q.18 Poisson’s ratio is defined as:
Lateral strain/Longitudinal strain
Stress/Strain
Shear strain/Shear stress
Volumetric strain/Stress
Explanation - Poisson’s ratio is the ratio of lateral contraction to longitudinal extension in elastic deformation.
Correct answer is: Lateral strain/Longitudinal strain
Q.19 The phenomenon of rise or fall of a liquid in a narrow tube is called:
Surface tension
Capillarity
Viscosity
Elasticity
Explanation - Capillary action refers to rise or depression of liquid in narrow tubes due to adhesion and cohesion.
Correct answer is: Capillarity
Q.20 The unit of surface tension is:
N/m
N/m²
Joule
Watt
Explanation - Surface tension is force per unit length, with SI unit Newton per meter.
Correct answer is: N/m
Q.21 Which law governs the elastic behavior of materials within elastic limits?
Newton's law
Hooke's law
Stoke's law
Bernoulli's principle
Explanation - Hooke’s law governs elastic behavior for small deformations.
Correct answer is: Hooke's law
Q.22 Liquids rise in a capillary tube if the angle of contact is:
0°
< 90°
> 90°
180°
Explanation - When adhesive force dominates, angle of contact < 90° and liquid rises.
Correct answer is: < 90°
Q.23 When a body is completely immersed in a liquid, the apparent loss of weight equals:
Weight of liquid displaced
Mass of body
Volume of liquid displaced
Density of liquid × g
Explanation - By Archimedes’ principle, apparent loss of weight = weight of displaced liquid.
Correct answer is: Weight of liquid displaced
Q.24 Which type of strain is produced when equal and opposite forces act tangentially?
Longitudinal strain
Lateral strain
Shear strain
Volumetric strain
Explanation - Tangential forces distort shape without changing volume, producing shear strain.
Correct answer is: Shear strain
Q.25 The SI unit of modulus of elasticity is:
N/m
N/m²
Joule
Pascal
Explanation - Elastic modulus is stress/strain; stress unit is Pascal, hence modulus has unit Pascal.
Correct answer is: Pascal