STRENGTH OF MATERIAL MCQ SET 10
Q1. Maximum shear stress in a two-dimensional stress system is:
A) (ฯโ – ฯโ)/2
B) (ฯโ + ฯโ)/2
C) (ฯโ/ฯโ)
D) (ฯโ ร ฯโ)/2
Answer: A) (ฯโ – ฯโ)/2
Explanation: The difference of principal stresses divided by two gives maximum shear stress.
Q2. The graphical method for finding principal stresses is:
A) Youngโs diagram
B) Mohrโs circle
C) Hookeโs law
D) Stress-strain curve
Answer: B) Mohrโs circle
Explanation: Mohrโs 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
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
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
Answer: C) Maximum stress a material can withstand for infinite cycles
Explanation: Itโs 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
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
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) mโด
B) mยณ
C) mยฒ
D) m
Answer: B) mยณ
Explanation: Since I has mโด and y has m, I/y gives units of mยณ.
Q9. The product of stress and strain is:
A) Force
B) Energy per unit volume
C) Modulus
D) None
Answer: B) Energy per unit volume
Explanation: Stress ร strain gives the strain energy density (J/mยณ).
Q10. In pure bending, the bending moment is:
A) Constant along the length
B) Varies linearly
C) Zero
D) Maximum at supports
Answer: A) Constant along the length
Explanation: In pure bending, the beam experiences constant bending moment and zero shear force.
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