Strength of Material MCQ Set 5
STRENGTH OF MATERIAL MCQ SET 5
Q1. The relation between Young’s modulus (E), shear modulus (G), and Poisson’s ratio (ν) is:
A) E = 2G(1 + ν)
B) E = G(1 + 2ν)
C) E = 3G(1 + ν)
D) E = G/ν
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Answer: A) E = 2G(1 + ν)
Explanation: This formula relates elasticity constants of isotropic materials.
Q2. The total angle of twist (θ) in a shaft is directly proportional to:
A) Torque
B) Length of shaft
C) Inversely proportional to G and J
D) All of the above
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Answer: D) All of the above
Explanation: θ = TL / GJ → proportional to T and L, inversely to G and J.
Q3. The section modulus of a beam is defined as:
A) I/y
B) y/I
C) M/σ
D) Both A and C
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Answer: D) Both A and C
Explanation: Section modulus Z = I/y = M/σ, measures bending strength of section.
Q4. When a material is subjected to shear stress, the strain produced is:
A) Longitudinal
B) Lateral
C) Angular
D) Volumetric
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Answer: C) Angular
Explanation: Shear stress produces angular deformation.
Q5. The maximum shear stress in a circular shaft is:
A) 16T/πD³
B) 32T/πD³
C) 64T/πD³
D) 8T/πD³
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Answer: B) 32T/πD³
Explanation: For solid circular shafts, τmax = 16T/πr³ = 32T/πD³.
Q6. The point of contraflexure occurs where:
A) Shear force is maximum
B) Bending moment is zero
C) Bending moment changes sign
D) Shear stress is zero
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Answer: C) Bending moment changes sign
Explanation: Contraflexure means “change of curvature” in bending moment diagram.
Q7. A simply supported beam with a UDL has maximum deflection at:
A) Quarter span
B) Mid-span
C) Support
D) One-third span
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Answer: B) Mid-span
Explanation: The center experiences maximum deflection for UDL beams.
Q8. Moment of inertia of a circular section about its diameter is:
A) πd⁴/32
B) πd⁴/64
C) πd⁴/16
D) πd⁴/8
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Answer: B) πd⁴/64
Explanation: I = πd⁴ / 64 for solid circular sections.
Q9. When a body is under torsion, which stress is developed?
A) Normal stress
B) Shear stress
C) Compressive stress
D) Tensile stress
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Answer: B) Shear stress
Explanation: Torsion always produces shear stress over the cross-section.
Q10. The maximum bending stress in a beam is directly proportional to:
A) Bending moment
B) Section modulus
C) Moment of inertia
D) Radius of gyration
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Answer: A) Bending moment
Explanation: From σ = M/Z, stress increases linearly with bending moment.