Young’s Modulus MCQ – Strength of Materials

1. The ratio of linear stress to linear strain is called

  1. Modulus of elasticity
  2. Bulk modulus
  3. Rigidity modulus
  4. Poisson’s ratio
Answer
Answer. c

2. Young’s modulus of a perfectly rigid body is

  1. Unity
  2. Negative
  3. Infinity
  4. Zero
  5. A non-zero, finite constant
Answer
Answer. c

3. A rod of uniform cross-section A and length L is deformed by δ, when subjected to a normal force P. The Young’s Modulus E of the material is,

$\\a.\; E=\frac{P\delta }{AL}\\ b.\; E=\frac{A\delta }{PL}\\ c.\; E=\frac{PL}{A\delta}\\ d.\; E=\frac{AL}{P\delta}$

Answer
Answer. c

4. If material is heated up, its Elastic modulus

  1. decreases
  2. increases
  3. remains constant
  4. none of the above
Answer
Answer. a

5. Young’s Modulus is the ratio of the normal stress to the

  1. longitudinal stress within proportional limit
  2. longitudinal stress as yield point
  3. normal strain within elastic limit
  4. reciprocal of normal strain within elastic limit
Answer
Answer. c

6. A metal bar of 10 mm diameter when subjected to a pull of 23.5 kN gave an elongation of 0.3 mm on a gauge length of 200 mm. The Young’s modulus of elasticity of the metal will nearly be

  1. 200 kN/mm2
  2. 300 kN/mm2
  3. 360 kN/mm2
  4. 400 kN/mm2
Answer
Answer. a

7. The ratio between tensile stress and tensile strain or compresive stress and compressive strain is termed as

  1. modulus of rigidity
  2. modulus of elasticity
  3. bulk modulus
  4. modulus of subgrade reaction
Answer
Answer. b

8. The relationship between Young’s modulus and shear modulus when (1/m) = 0, is

  1. E = 2G
  2. E = 3G
  3. E = 2G + 1
  4. G = 2E
Answer
Answer. a

9. Modulus of elasticity is

  1. Compressive stress/Tensile strain
  2. Tensile stress/Compressive stress
  3. Compressive stress/Compressive strain
  4. Tensile stress/ Compressive or tensile strain
Answer
Answer. c

10. The ratio of young’s modulus to the bulk modulus is

  1. More than one third
  2. Less than one third
  3. Less than one half
  4. None of the above
Answer
Answer. a

11. In a bar of length L, diameter D and cross-sectional area A, the strain produced is S under the action of load W. The Young’s modulus of elasticity for the wire is

  1. W/DLS
  2. WL/DS
  3. W/AS
  4. SDA/WL
Answer
Answer. c

12. The ratio of Young’s modulus of high tensile steel to that of mild steel is about

  1. 0.5
  2. 1.0
  3. 1.5
  4. 2.0
Answer
Answer. b

13. Two bars of same area and length but of different materials are subjected to same tensile force. If the bars have their axial elongation in the ratio of 4:6, then the ratio of modulus of elasticity of the two materials would be

  1. 4 : 6
  2. 6 : 4
  3. 2 : $\sqrt{6}$
  4. $\sqrt{6}$ : 2
Answer
Answer. b

14. Two bars of different materials and same size are subjected to the same tensile force. If the bars have unit elongation in the ratio of 3:5, then the ratio of modulus of elasticity of the two materials will be

  1. 3:5
  2. 2:5
  3. 3:4
  4. 5:3
Answer
Answer. d

15. The modulus of elasticity of rolled structural mild steel is about

  1. 2 × 105 MPa
  2. 2 × 106 MPa
  3. 2 × 107 MPa
  4. 2 × 108 MPa
Answer
Answer. a

16. The unit of modulus of elasticity is same as those of

  1. Stress, strain and pressure
  2. Stress, force and modulus of rigidity
  3. Stress, pressure and modulus of rigidity
  4. Strain, force & pressure
Answer
Answer. c

17. For a material, the modulus of Rigidity is 100 GPa and Poisson’s ratio is 0.25. The value of elastic modulus in GPa is

  1. 100
  2. 150
  3. 200
  4. 250
Answer
Answer. d

18. If Poisson’s ratio of a material is 0.5, then the elastic modulus for the material is

  1. Three times its shear modulus
  2. Four times its shear modulus
  3. Equal to its shear modulus
  4. Indeterminate
Answer
Answer. a