Strength of Material MCQ Set 10

STRENGTH OF MATERIAL MCQ SET 10

Q1. Maximum shear stress in a two-dimensional stress system is:

A) (σ₁ – σ₂)/2
B) (σ₁ + σ₂)/2
C) (σ₁/σ₂)
D) (σ₁ × σ₂)/2

Show Answer

Answer: A) (σ₁ – σ₂)/2
Explanation: The difference of principal stresses divided by two gives maximum shear stress.

Q2. The graphical method for finding principal stresses is:

A) Young’s diagram
B) Mohr’s circle
C) Hooke’s law
D) Stress-strain curve

Show Answer

Answer: B) Mohr’s circle
Explanation: Mohr’s circle represents the state of stress graphically on a 2D plane.

Q3. A material that breaks suddenly without much deformation is called:

A) Ductile
B) Brittle
C) Elastic
D) Plastic

Show Answer

Answer: B) Brittle
Explanation: Brittle materials fail with little plastic deformation (e.g., cast iron, glass).

Q4. Fatigue failure occurs due to:

A) Static load
B) Repeated or fluctuating load
C) Gradual load
D) Sudden load

Show Answer

Answer: B) Repeated or fluctuating load
Explanation: Fatigue results from repeated cyclic loading even below yield stress.

Q5. The endurance limit is:

A) Ultimate stress
B) Yield stress
C) Maximum stress a material can withstand for infinite cycles
D) Breaking stress

Show Answer

Answer: C) Maximum stress a material can withstand for infinite cycles
Explanation: It’s the stress level below which a material can endure infinite stress cycles.

Q6. The factor of safety is defined as:

A) Ultimate stress / Working stress
B) Working stress / Ultimate stress
C) Yield stress / Ultimate stress
D) Strain / Stress

Show Answer

Answer: A) Ultimate stress / Working stress
Explanation: It ensures design safety by providing margin between actual and failure loads.

Q7. The section modulus is given by:

A) I/y
B) I/A
C) y/I
D) I/L

Show Answer

Answer: A) I/y
Explanation: Section modulus = I/y, it measures the bending strength of a section.

Q8. The unit of section modulus is:

A) m⁴
B) m³
C) m²
D) m

Show Answer

Answer: B) m³
Explanation: Since I has m⁴ and y has m, I/y gives units of m³.

Q9. The product of stress and strain is:

A) Force
B) Energy per unit volume
C) Modulus
D) None

Show Answer

Answer: B) Energy per unit volume
Explanation: Stress × strain gives the strain energy density (J/m³).

Q10. In pure bending, the bending moment is:

A) Constant along the length
B) Varies linearly
C) Zero
D) Maximum at supports

Show Answer

Answer: A) Constant along the length
Explanation: In pure bending, the beam experiences constant bending moment and zero shear force.