Q.1 What is the SI unit of Young's modulus?
Pascal
Newton
Joule
Watt
Explanation - Young’s modulus is defined as stress/strain. Since stress is in Pascal and strain is dimensionless, the unit remains Pascal.
Correct answer is: Pascal
Q.2 Which property is measured using Young’s modulus?
Elasticity
Plasticity
Rigidity
Fluidity
Explanation - Young's modulus measures the ability of a material to regain its original length after being stretched or compressed.
Correct answer is: Elasticity
Q.3 The bulk modulus relates which two quantities?
Pressure and volume strain
Stress and strain
Force and displacement
Energy and work
Explanation - Bulk modulus is defined as the ratio of pressure applied to the volumetric strain produced in a body.
Correct answer is: Pressure and volume strain
Q.4 Which modulus is associated with the twisting of a body?
Young’s modulus
Bulk modulus
Shear modulus
Poisson’s ratio
Explanation - Shear modulus relates shear stress to shear strain, which occurs during twisting or shearing deformations.
Correct answer is: Shear modulus
Q.5 Poisson’s ratio is defined as:
Lateral strain / Longitudinal strain
Stress / Strain
Pressure / Volume strain
Shear stress / Shear strain
Explanation - Poisson’s ratio quantifies the contraction perpendicular to applied stress relative to the elongation along it.
Correct answer is: Lateral strain / Longitudinal strain
Q.6 For an ideal material, Poisson’s ratio cannot exceed:
0.25
0.33
0.50
1.00
Explanation - Poisson’s ratio ranges from 0 to 0.5 for stable, isotropic materials.
Correct answer is: 0.50
Q.7 Which law states that stress is directly proportional to strain within elastic limit?
Hooke’s law
Boyle’s law
Pascal’s law
Newton’s law
Explanation - Hooke’s law describes the linear relationship between stress and strain for small deformations within elastic limit.
Correct answer is: Hooke’s law
Q.8 If the length of a wire doubles and radius becomes half, what happens to its stretching under same force?
Remains same
Doubles
Quadruples
Becomes one-fourth
Explanation - Extension ∆L = FL / AY. If L doubles and A becomes one-fourth, ∆L increases by factor of 8.
Correct answer is: Quadruples
Q.9 The work done per unit volume in stretching a wire is:
Stress × Strain
½ Stress × Strain
Stress / Strain
Strain / Stress
Explanation - Elastic potential energy density = (1/2) × Stress × Strain.
Correct answer is: ½ Stress × Strain
Q.10 The dimensional formula of Young’s modulus is same as:
Force
Pressure
Energy
Work
Explanation - Young’s modulus has units of stress (force/area), which is same as pressure.
Correct answer is: Pressure
Q.11 Which of the following is dimensionless?
Young’s modulus
Poisson’s ratio
Bulk modulus
Stress
Explanation - Poisson’s ratio is a ratio of two strains, hence dimensionless.
Correct answer is: Poisson’s ratio
Q.12 If a wire is stretched and then released, the property that allows it to return to its original length is:
Plasticity
Elasticity
Ductility
Malleability
Explanation - Elasticity refers to the ability of a material to regain its original shape after deformation.
Correct answer is: Elasticity
Q.13 What is the unit of stress?
N
N/m²
J
J/m³
Explanation - Stress = Force / Area, unit is Newton per square meter (Pascal).
Correct answer is: N/m²
Q.14 The elastic limit is the maximum stress that a material can withstand without:
Breaking
Permanent deformation
Losing weight
Changing color
Explanation - Elastic limit is the stress beyond which the material undergoes plastic deformation and cannot return to original shape.
Correct answer is: Permanent deformation
Q.15 Which of the following materials has the highest Young’s modulus?
Rubber
Steel
Copper
Aluminium
Explanation - Steel is much stiffer than rubber or other metals, hence it has the highest Young’s modulus among the given options.
Correct answer is: Steel
Q.16 In which region of the stress-strain curve is Hooke’s law valid?
Plastic region
Elastic region
Yield point
Breaking point
Explanation - Hooke’s law holds true in the elastic region, where stress is proportional to strain.
Correct answer is: Elastic region
Q.17 A long wire is stretched by a force. The strain produced is independent of:
Length of wire
Cross-sectional area
Applied force
Young’s modulus
Explanation - Strain = ∆L / L. ∆L itself is proportional to L, so strain does not depend on L.
Correct answer is: Length of wire
Q.18 The ratio of longitudinal stress to longitudinal strain is:
Bulk modulus
Young’s modulus
Shear modulus
Poisson’s ratio
Explanation - Young’s modulus is defined as longitudinal stress / longitudinal strain.
Correct answer is: Young’s modulus
Q.19 Which quantity has the same dimension as stress?
Energy density
Force
Torque
Momentum
Explanation - Stress = Force/Area (N/m²), Energy density = Energy/Volume (J/m³). Both have the same dimension.
Correct answer is: Energy density
Q.20 A steel wire of length L and cross-sectional area A is stretched by a force F. The extension is proportional to:
F
F/A
FL/A
FL/AY
Explanation - ∆L = FL / AY according to Young’s modulus definition.
Correct answer is: FL/AY
Q.21 Which factor does NOT affect the extension of a wire under load?
Length
Cross-sectional area
Material
Temperature of surroundings
Explanation - Extension depends on F, L, A, and material’s Young’s modulus. Normal ambient temperature has negligible effect.
Correct answer is: Temperature of surroundings
Q.22 What is the unit of strain?
No unit
Pascal
Newton
Joule
Explanation - Strain = ∆L/L is a ratio of lengths, hence dimensionless.
Correct answer is: No unit
Q.23 The slope of the linear portion of stress-strain curve represents:
Poisson’s ratio
Elastic limit
Young’s modulus
Breaking stress
Explanation - In the linear region, stress ∝ strain, slope = stress/strain = Young’s modulus.
Correct answer is: Young’s modulus
Q.24 Which material property allows metals to be drawn into thin wires?
Elasticity
Malleability
Ductility
Rigidity
Explanation - Ductility is the property of being drawn into thin wires without breaking.
Correct answer is: Ductility
Q.25 The ability of a material to resist a force without permanent deformation is:
Elasticity
Plasticity
Malleability
Ductility
Explanation - Elasticity refers to returning to original shape after deformation ends.
Correct answer is: Elasticity