1) Whenever an external system of forces acts on a body, the resistance per unit area to deformation is called:
A. Strain
B. Stress
C. Pressure
D. Modulus of Elasticity
Quick Revision Notes
Stress and Strain: Important AMVI Points
💪 Stress
Internal resistance per unit area developed in a material due to external force.
σ = P / A
📏 Strain
Deformation per unit original length. It has no unit because it is a ratio.
ε = ΔL / L
⚖️ Hooke's Law
Within elastic limit, stress is directly proportional to strain.
σ ∝ ε
🛡️ Factor of Safety
Ratio of ultimate stress to working stress. It is always greater than 1.
FOS = Ultimate / Working
Must Remember Values and Formulas
- Stress unit in SI: N/m² or Pascal.
- Young's modulus of mild steel: approximately 210 kN/mm² or 210 GPa.
- Poisson's ratio of steel: approximately 0.25 to 0.33.
- Poisson's ratio of cast iron: approximately 0.23 to 0.27.
- Poisson's ratio of rubber: approximately 0.50.
- Stress-strain curve order: Proportional limit → Elastic limit → Yielding → Ultimate stress → Failure.
- Young's modulus: E = Linear stress / Linear strain.
- Modulus of rigidity: G = Shear stress / Shear strain.
- Bulk modulus: K = Direct stress / Volumetric strain.
- Change in length of a bar: δL = PL / AE.
AMVI Expected MCQs
Practice Questions with Explanation
2) The unit of stress in SI units is:
A. N/mm²
B. kN/mm²
C. N/m²
D. Any one of these
3) The deformation per unit length is called:
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Strain
4) When a body is subjected to two equal and opposite pulls, the stress and strain induced are:
A. Compressive stress, tensile strain
B. Tensile stress, compressive strain
C. Tensile stress, tensile strain
D. Compressive stress, compressive strain
5) Tangential forces causing sliding of layers produce:
A. Tensile stress, tensile strain
B. Compressive stress, compressive strain
C. Shear stress, tensile strain
D. Shear stress, shear strain
6) Hooke's law holds good up to:
A. Yield point
B. Elastic limit
C. Plastic limit
D. Breaking point
7) The ratio of linear stress to linear strain is called:
A. Modulus of Rigidity
B. Modulus of Elasticity
C. Bulk Modulus
D. Poisson's Ratio
8) The modulus of elasticity for mild steel is approximately:
A. 10 kN/mm²
B. 80 kN/mm²
C. 100 kN/mm²
D. 210 kN/mm²
9) The ratio of lateral strain to linear strain is called:
A. Modulus of elasticity
B. Modulus of rigidity
C. Bulk modulus
D. Poisson's ratio
10) The stress at which extension takes place more quickly as compared to increase in load is called:
A. Elastic limit
B. Yield point
C. Ultimate point
D. Breaking point
11) The tensile test is mainly carried on ______ materials.
A. Ductile
B. Brittle
C. Malleable
D. Plastic
12) The compression test is mainly carried on ______ materials.
A. Ductile
B. Brittle
C. Malleable
D. Plastic
13) Factor of safety is defined as the ratio of:
A. Ultimate stress to working stress
B. Working stress to ultimate stress
C. Breaking stress to ultimate stress
D. Ultimate stress to breaking stress
🏆 100+ Rank Holders | 🔥 Rank-Focused AMVI Training
🚀 AMVI Complete Preparation Program
Live Classes • Recorded Sessions • Mock Tests • Previous Question Discussions • Study Materials • Revision Sessions
Join InspirePSC AMVI Online Coaching for Kerala PSC AMVI Preparation with mechanical, automobile and MVI Act sessions from one of the best AMVI coaching centres in Kerala.