The property of a material to regain its original shape after deformation is called:
A Plasticity
B Elasticity
C Ductility
D Rigidity
Elasticity is the ability of a body to return to its original configuration after deforming forces are removed.
Young’s modulus has the same dimension as:
A Energy
B Pressure
C Force
D Velocity
Young’s modulus = Stress/Strain → (Force/Area) = Pressure.
A wire is stretched by a force F. The strain produced depends on:
A Length only
B Area only
C Both length and area
D Density
Strain = ΔL/L; change in length ΔL ∝ F/A. So both L and area A matter.
Bulk modulus relates to change in:
A Length
B Shape
C Volume
D Mass
Bulk modulus measures resistance to volume change under pressure.
A material with high Young’s modulus is:
A Highly stretchable
B Very soft
C Rigid
D Brittle only
Greater Young’s modulus → greater resistance to deformation → rigidity.
Shear modulus is defined as ratio of:
A Tensile stress/tensile strain
B Shearing stress/shearing strain
C Bulk stress/volume strain
D Pressure/temperature
Shear modulus corresponds to shearing stress divided by angular deformation.
When a spring is stretched, potential energy stored depends on:
A k only
B x only
C Both k and x²
D 1/x
Elastic potential energy = ½ kx².
Steel is preferred over rubber in construction because it has:
A Lower elasticity
B Higher elastic limit
C Higher ductility
D Greater thermal conductivity
Steel has a high elastic limit, allowing safe load limits.
A body is perfectly plastic when:
A Stress ∝ strain
B It returns fully after stress removal
C It does not return to original shape
D Stress is zero
A perfectly plastic body does not regain shape after deformation.
Poisson’s ratio is ratio of:
A Longitudinal strain to lateral strain
B Pressure to volume
C Stress to strain
D Area to volume
Poisson’s ratio = lateral strain / longitudinal strain.
Pressure in a fluid at a depth h is proportional to:
A h only
B ρh
C ρhg
D 1/h
Hydrostatic pressure P = ρgh.
A floating object displaces water equal to its:
A Weight
B Volume
C Density
D Area
Archimedes’ principle: buoyant force = weight of displaced fluid.
The SI unit of pressure is:
A Dyne
B Pascal
C Torr
D Watt
Pressure = N/m² = Pascal.
Streamlines are closer where fluid speed is:
A Lower
B Higher
C Zero
D Same everywhere
Closer streamlines → higher velocity according to continuity.
Bernoulli’s theorem is based on conservation of:
A Momentum
B Mass
C Energy
D Pressure
Bernoulli’s equation results from conservation of mechanical energy.
A hydraulic lift works due to:
A Bernoulli’s law
B Pascal’s law
C Archimedes’ principle
D Boyle’s law
Fluids transmit pressure equally in all directions.
Terminal velocity increases with:
A Increasing viscosity
B Decreasing radius
C Increasing radius
D Decreasing density difference
For a sphere, vₜ ∝ r².
The continuity equation expresses conservation of:
A Energy
B Volume
C Mass
D Pressure
For incompressible flow, A₁v₁=A₂v₂ (mass continuity).
A body sinks if its density is:
A Less than fluid
B Equal to fluid
C Greater than fluid
D Zero
Higher-density objects cannot be supported by buoyant force.
The unit of surface tension is:
A N/m²
B N/m
C J
D Pa
Surface tension = Force per unit length.
Viscosity arises due to:
A Gravity
B Intermolecular forces
C Pressure
D Volume
Internal friction is from molecular interactions.
Stokes’ law holds for:
A Turbulent flow
B High velocity
C Very small spheres at low speeds
D Compressible fluids
Stokes’ law applies to laminar flow at low Reynolds number.
Capillary rise is more in:
A Wide tubes
B Narrow tubes
C Any tube equally
D Rough tubes only
h ∝ 1/r.
Detergents reduce surface tension by:
A Increasing cohesion
B Decreasing adhesion
C Decreasing cohesion
D Increasing temperature
They weaken intermolecular attraction, reducing surface tension.
A drop of water is spherical due to:
A Gravity
B Viscosity
C Surface tension
D Temperature
Surface tension minimizes surface area → sphere.
Temperature increase generally:
A Increases viscosity of liquids
B Decreases viscosity of liquids
C Has no effect
D Makes viscosity infinite
Liquid viscosity decreases with temperature.
Terminal velocity in a viscous medium is zero when:
A Buoyant force > weight
B Weight > drag
C Buoyant force = weight
D Weight = buoyant force + viscous drag
At terminal velocity net force = 0.
Surface energy per unit area equals:
A Viscosity
B Surface tension
C Thermal conductivity
D Stress
Surface energy and surface tension have same value dimensionally.
Soap bubbles form due to:
A Density
B Very high pressure
C Surface tension
D Buoyancy
They minimize energy by forming spherical surfaces.
Viscosity of gases:
A Decreases with temperature
B Increases with temperature
C Zero
D Independent of temperature
Higher temperature → faster molecular motion → more momentum transfer.
Temperature is a measure of:
A Total energy
B Heat
C Average kinetic energy
D Pressure
Temperature relates to average kinetic energy of molecules.
Heat capacity depends on:
A Material only
B Mass only
C Both mass & nature
D Temperature only
Heat capacity C = mc.
Linear expansion is proportional to:
A Volume
B Temperature change
C Density
D Pressure
ΔL ∝ ΔT.
The SI unit of heat is:
A Calorie
B Newton
C Joule
D Watt
Joule is SI unit.
The relation between Cp and Cv for solids is:
A Cp = Cv
B Cp > Cv
C Cp < Cv
D Cp = 0
For solids, difference is negligible.
Specific heat is highest for:
A Iron
B Copper
C Water
D Gold
Water has highest specific heat capacity.
Sublimation involves:
A Solid → liquid
B Liquid → gas
C Solid → gas
D Gas → solid
Direct transition.
Thermal conductivity is lowest in:
A Metals
B Water
C Air
D Glass
Gases are poor conductors.
In conduction, heat flows due to:
A Bulk motion
B Radiation
C Direct contact
D Convection cells
Conduction requires contact.
Latent heat refers to heat used in:
A Temperature change
B Phase change
C Expansion
D Radiation
Latent heat changes state without temperature change.
Pressure of a gas arises due to:
A Weight of gas
B Viscosity
C Molecular collisions with walls
D Surface tension
Molecules exert force during collisions.
RMS speed of gas molecules is proportional to:
A √T
B T
C 1/T
D 1/√T
v_rms = √(3RT/M).
At constant temperature, pressure × volume is constant. This is:
A Charle’s law
B Boyle’s law
C Avogadro’s law
D Gay–Lussac law
Boyle’s law: PV = constant.
Avogadro’s law states:
A PV ∝ T
B Equal volumes contain equal mass
C Equal volumes at STP contain equal number of molecules
D Pressure ∝ temperature
Avogadro: same volume → same number of molecules.
Internal energy of an ideal gas depends on:
A Volume
B Temperature
C Pressure
D Density
U ∝ temperature only.
Zeroth law defines:
A Entropy
B Internal energy
C Temperature
D Heat
It gives basis for temperature measurement.
First law of thermodynamics is based on:
A Conservation of mass
B Conservation of energy
C Conservation of momentum
D Conservation of heat
ΔQ = ΔU + W.
In an isothermal process, ΔU =
A 0
B Maximum
C Minimum
D Infinite
Temperature constant → internal energy constant.
Work done in an adiabatic expansion is:
A Zero
B Maximum
C Minimum
D Negative
No heat exchange → greater work than isothermal.
Efficiency of a Carnot engine depends on:
A Working substance
B Type of fuel
C Temperature difference
D Volume
η = 1 − T₂/T₁.