Strength of Material MCQ Set 3

STRENGTH OF MATERIAL MCQ SET 3

Q1. The phenomenon of slow and permanent deformation under constant load is:

A) Fatigue
B) Creep
C) Elasticity
D) Plasticity

Show Answer

Answer: B) Creep
Explanation: Creep occurs at high temperature over long time under steady stress .

Q2. The maximum strain energy stored in a body without permanent deformation is:

A) Modulus
B) Resilience
C) Toughness
D) Elasticity

Show Answer

Answer: B) Resilience
Explanation: Resilience is the capacity of a material to absorb energy within elastic limit.

Q3. The energy absorbed till fracture is called:

A) Toughness
B) Resilience
C) Elasticity
D) Plasticity

Show Answer

Answer: A) Toughness
Explanation: Toughness = area under the entire stress-strain curve.

Q4. The elongation in a bar due to self-weight is maximum at:

A) Top
B) Bottom
C) Middle
D) Uniform throughout

Show Answer

Answer: B) Bottom
Explanation: Stress increases linearly with depth, so elongation is greatest at the bottom.

Q5. The value of Poisson’s ratio for steel is approximately:

A) 0.1
B) 0.3
C) 0.5
D) 0.8

Show Answer

Answer: B) 0.3
Explanation: For most steels, Poisson’s ratio ≈ 0.25–0.3.

Q6. The bending stress in a beam is maximum at:

A) Neutral axis
B) Outer surface
C) Centroid
D) Mid-span

Show Answer

Answer: B) Outer surface
Explanation: Bending stress varies linearly from zero at the neutral axis to maximum at the outermost fiber.

Q7. The neutral axis in a beam passes through:

A) Top fiber
B) Bottom fiber
C) Centroid of the cross-section
D) Midpoint of the beam

Show Answer

Answer: C) Centroid of the cross-section
Explanation: The neutral axis is located at the centroid where bending stress is zero.

Q8. The relationship between bending moment (M), stress (σ), and section modulus (Z) is:

A) M = σ × Z
B) M = Z / σ
C) M = σ / Z
D) M = Z × σ²

Show Answer

Answer: A) M = σ × Z
Explanation: Bending moment equals stress multiplied by the section modulus.

Q9. The deflection of a cantilever beam carrying a point load at its free end is:

A) WL³/3EI
B) WL³/6EI
C) WL³/8EI
D) WL³/2EI

Show Answer

Answer: A) WL³/3EI
Explanation: For cantilever with point load at free end: δ = WL³ / (3EI).

Q10. The shear stress in a circular shaft subjected to torque varies:

A) Linearly from center to surface
B) Uniformly throughout
C) Parabolically
D) Not at all

Show Answer

Answer: A) Linearly from center to surface
Explanation: Shear stress is zero at center and maximum at outer surface.