Bending Stress in Beams MCQ – Objective Questions with Answers
Mechanical Engineering › Strength of Materials | Free practice MCQs with detailed explanations
Last Updated: June 2026
📌 About this MCQ Set
Bending stress is the normal stress induced in a beam due to an applied bending moment. The flexure formula relates bending moment, stress and the geometry of the cross-section.
These MCQs cover the flexure formula, neutral axis, section modulus and stress distribution.
8 questions • every answer comes with a worked explanation. Click Show Answer to check yourself.
📖 New to this topic? Read the full concept guide: Bending Stress in Beams →
Bending Stress in Beams MCQs
Q1. The flexure (bending) formula is:
Show Answer
Answer: A. M/I = σ/y = E/R
The flexure formula: M/I = σ/y = E/R, relating moment, second moment of area, stress, distance from NA, modulus and radius of curvature.
Q2. Bending stress is maximum at:
Show Answer
Answer: B. The extreme fibre (farthest from NA)
Bending stress varies linearly with distance from the neutral axis, so it is maximum at the extreme fibre.
Q3. Bending stress at the neutral axis is:
Show Answer
Answer: B. Zero
At the neutral axis y = 0, so bending stress is zero.
Q4. The neutral axis of a beam section passes through its:
Show Answer
Answer: B. Centroid
For pure bending, the neutral axis passes through the centroid of the cross-section.
Q5. Section modulus Z is defined as:
Show Answer
Answer: B. I / y_max
Section modulus Z = I / y_max; bending strength is proportional to Z.
Q6. For a rectangular section of width b and depth d, the section modulus is:
Show Answer
Answer: A. bd²/6
Z = I/y_max = (bd³/12)/(d/2) = bd²/6.
Q7. Bending stress at a fibre distance y from the neutral axis is:
Show Answer
Answer: B. M·y/I
σ = M·y / I from the flexure formula.
Q8. The moment of resistance of a beam section equals:
Show Answer
Answer: B. σ × Z
Moment of resistance = σ_allowable × Z, which must be ≥ applied bending moment.
Frequently Asked Questions
What is bending stress?
The normal (tensile or compressive) stress induced in the fibres of a beam due to an applied bending moment; it is zero at the neutral axis and maximum at the extreme fibres.
What is the flexure formula?
M/I = σ/y = E/R, relating bending moment, second moment of area, bending stress, distance from the neutral axis, elastic modulus and radius of curvature.
What is section modulus?
Z = I/y_max, a geometric property of the cross-section that measures its bending strength.