Structures · MCQ practice Stress and Strain MCQs – Part 1
15 questions. Tap an option to check it instantly, then read the solution.
Part 1 of 3
Practice SSC JE and other civil engineering exam questions on stress and strain: Hooke's law, Young's modulus, modulus of rigidity, bulk modulus, Poisson's ratio and the relations between elastic constants, volumetric strain, the stress–strain curve of mild steel, composite bars, thermal stress, strain energy and suddenly applied loads. Tap an option to check it, then open the full explanation for each question.
Question 1 Medium
A material has linear strains of 0.05, 0.10 and 0.10 along the X, Y and Z directions. The hydrostatic stress at the point is 25 N/mm². Calculate the bulk modulus.
A 125 N/mm² B 100 N/mm² C 500 N/mm² D 250 N/mm²
Answer: B. 100 N/mm²
εv = 0.05 + 0.10 + 0.10 = 0.25; K = p/εv = 25/0.25 = 100 N/mm².
Question 2 Medium
Linear strains along X, Y and Z in a homogeneous object are 0.05, 0.10 and 0.10. The object measured 20 cm × 10 cm × 10 cm before deformation. Find the volumetric strain and the change in volume.
A Volumetric strain = 0.25, change in volume = 5 × 10⁵ mm³ B Volumetric strain = 0.7, change in volume = 1400 cm³ C Volumetric strain = 0.3, change in volume = 60 × 10⁴ mm³ D Volumetric strain = 0.25, change in volume = 500 mm³
Answer: A. Volumetric strain = 0.25, change in volume = 5 × 10⁵ mm³
εv = 0.25; V = 2000 cm³; ΔV = 0.25 × 2000 = 500 cm³ = 5 × 10⁵ mm³.
Question 3 Easy
Calculate the bulk modulus of an alloy whose modulus of elasticity is 180 GPa and Poisson's ratio is 0.25.
A 120 GPa B 140 GPa C 100 GPa D 160 GPa
Answer: A. 120 GPa
K = E/[3(1 − 2μ)] = 180/(3 × 0.5) = 120 GPa.
Question 4 Easy
What is the meaning of biaxial stress?
A Stress acting along only one axis B Stress acting along two axes C Stress acting along the tangential direction only D Stress acting along more than two axes
Answer: B. Stress acting along two axes
Biaxial = normal stresses along two mutually perpendicular axes (a two-dimensional state of stress).
Question 5 Easy
Poisson's ratio for a linear elastic, homogeneous and isotropic material:
A varies linearly with stress B is not the same for tension and compression C remains constant throughout D is in the range 0 to 1
Answer: C. remains constant throughout
For such a material Poisson's ratio is a single material constant: the same everywhere, in all directions, and at all stress levels in the elastic range.
Question 6 Medium
Which of the following options is INCORRECT?
A Lateral strain can be measured along the transverse direction B Longitudinal strain acts along the longest dimension C −(Longitudinal strain ÷ Lateral strain) = Poisson's ratio D Lateral strain is generally less than longitudinal strain
Answer: C. −(Longitudinal strain ÷ Lateral strain) = Poisson's ratio
Poisson's ratio is −(lateral strain ÷ longitudinal strain); option (c) has it upside down.
Question 7 Easy
For an isotropic homogeneous body, the ratio of lateral strain to axial strain is called:
A modulus of elasticity B yield value C Poisson's ratio D plasticity index
Answer: C. Poisson's ratio
That ratio is Poisson's ratio.
Question 8 Medium
If E is the modulus of elasticity, N the modulus of rigidity and K the bulk modulus, which relation is correct?
A E = 9NK/(N + 3K) B E = 9NK/(3N + 3K) C E = 6NK/(N + 3K) D E = 9NK/(N + K)
Answer: A. E = 9NK/(N + 3K)
E = 9KN/(3K + N).
Question 9 Easy
Within the elastic limit of a material, the modulus of elasticity is the ratio of:
A area to strain B stress to area C stress to strain D strain to stress
Answer: C. stress to strain
E = stress ÷ strain.
Question 10 Easy
The net area of a round bar resisting tension is the area of cross-section at:
A the mid-section B the root of the thread C the difference of mid-section and root of the thread D None of these
Answer: B. the root of the thread
A threaded bar is weakest where the diameter is smallest — at the root of the thread.
Question 11 Medium
If all the dimensions of a prismatic bar are doubled, the maximum stress produced in it under its own weight will:
A decrease B increase to two times C increase to three times D None of these
Answer: B. increase to two times
Maximum self-weight stress = γL (at the top); it depends only on length, so doubling L doubles it.
Question 12 Easy
The value of Poisson's ratio of concrete lies approximately in the range:
A 0.4 to 0.47 B 0.31 to 0.35 C 0.15 to 0.2 D 0.25 to 0.3
Answer: C. 0.15 to 0.2
Concrete: μ ≈ 0.15–0.2 (IS 456 uses 0.2).
Question 13 Medium
The relation between bulk modulus K, Young's modulus E and Poisson's ratio 1/m is:
A K = mE/(3m) B K = mE/3 C K = E/[3(m − 2)] D K = mE/[3(m − 2)]
Answer: D. K = mE/[3(m − 2)]
E = 3K(1 − 2/m) ⇒ K = mE/[3(m − 2)].
Question 14 Medium
The phenomenon of slow extension of a material, increasing with time under a constant load, is called:
A Creeping B Breaking C Yielding D None of these
Answer: A. Creeping
Slow, time-dependent extension under a constant sustained load is creep. (The book's printed key gives yielding; see the note.)
Question 15 Easy
Poisson's ratio of rubber lies between:
A 0.25 and 0.33 B 0.08 and 0.18 C 0.45 and 0.50 D 0.23 and 0.27
Answer: C. 0.45 and 0.50
Rubber is nearly incompressible, so μ ≈ 0.45–0.5.
Part 1 of 3