1. Modulus of rigidity is defined as the ratio of
a) longitudinal stress to longitudinal strain
b) shear stress to shear strain
c) stress to strain
d) stress to volumetric strain
Ans: b
2. If the Young’s modulus of elasticity of a material is twice its modulus of rigidity, then the Poisson’s ratio of the material is
a) -1
b) -0.5
c) 0.5
d) zero
Ans: d
3. Limit of proportionality depends upon
a) area of cross-section
b) type of loading
c) type of material
d) all of the above
Ans: c
4. For an isotropic, homogeneous and elastic material obeying Hooke’s law, number of independent elastic constants is
a) 2
b) 3
c) 9
d) 1
Ans: a
5. In a thin cylindrical shell, the ratio of longitudinal stress to hoop stress is
a) 0.5
b) 1
c) 2
d) 4
Ans: c
6. If all the dimensions of a prismatic bar are doubled, then the maximum stress produced in it under its own weight will
a) decrease
b) remain unchanged
c) increase to two times
d) increase to four times
Ans: c
7. The relationship between Young’s, modulus of elasticity E, bulk modulus K and Poisson’s ratio u is given by
a) E = 2K(l-2u.)
b) E = 3K(l + u)
c) E = 3K(l-2u)
d) E = 2K(l + u)
Ans: c
8. Limiting values of Poisson’s ratio are
a) – 1 and 0.5
b) -land-0.5
c) 1 and – 0.5
d) 0 and 0.5
Ans: a
9. The elongation of a conical bar under its own weight is equal to
a) that of a prismatic bar of same length
b) one half that of a prismatic bar of same length
c) one third that of a prismatic bar of same length
d) one fourth that of a prismatic bar of same length
Ans: c
10. If a material has identical properties in all directions, it is said to be
a) homogeneous
b) isotropic
c) elastic
d) orthotropic
Ans: b
11. Two bars of different materials are of the same size and are subjected to same tensile forces. If the bars have unit elongations in the ratio of 4 : 7, then the ratio of moduli of elasticity of the two materials is
a) 7:4
b) 4:7
c) 4:17
d) 16 :49
Ans: a
12. A prismatic bar of volume V is subjected to a tensile force in longitudinal direction.
If Poisson’s ratio of the material is u and longitudinal strain is e, then the final volume of the bar becomes
a) (l + e)(l-u)2V
b) (l-e)2(l + ue)V
c) (l + e)(l-ne)2V
d) (l-ue)3V
Ans: c
13. If a composite bar of steel and copper is heated, then the copper bar will be under
a) tension
b) compression
c) shear
d) torsion
Ans: b
14. Effective length of a weld is equal to
a) overall length – weld size
b) overall length – throat thickness
c) overall length – 2 x weld size
d) overall length – 2 x throat thickness
Ans: c
15. Size of a right angled fillet weld is given by
a) 0.707 x throat thickness
b) 0.414 x throat thickness
c) 2.0 x throat thickness
d) throat thickness
Ans: b
16. The effective length of a fillet weld designed to transmit axial load shall not be less than
a) 2 x size of weld
b) 4 x size of weld
c) 6 x size of weld
d) 10 x size of weld
Ans: b
17. Size of fillet weld with unequal legs is equal to
a) smaller leg length
b) longer leg length
c) throat thickness
d) average of smaller and longer leg lengths
Ans: a
18. Weakest section in a fillet weld is
a) throat of the fillet
b) smaller side
c) side parallel to force
d) side perpendicular to force
Ans: a
19. Effective throat thickness of a fillet weld is
a) 0.707 x size of weld
b) 1.414 x size of weld
c) a function of the angle between fusion faces
d) equal to the side of the fillet
Ans: c
20. According to Unwin’s formula, the dia¬meter of rivet in mm to suit the t mm thickness of plate is given by
a) 6t
b) 6Vt
c) 1.9-y/t
d) 1.5 t+ 4
Ans: b
21. A flat carrying a pull of 69C kN is con-nected to a gusset plate using rivets. If the pulls required to shear the rivet, to crush the rivet and to tear the plate per pitch length are 68.5 kN, 46 kN and 69 kN respectively, then the number of rivets required is
a) 10
b) 12
c) 15
d) 20
Ans: c
22. If the rivet value is 16.8 kN and force in the member is 16.3 kN, then the number of rivets required for the connection of the member to a gusset plate is
a) 1
b) 2
c) 3
d) 4
Ans: b
23. At a point in a strained body carrying two unequal unlike principal stresses pi and p2 (Pi > P2X the maximum shear stress is given by
a) p,/2
b) p2/2
c) (p,-p2)/2
d) (p, + p2)/2
Ans: d
24. If a point in a strained material is subjected to equal normal and tangential stresses, then the angle of obliquity is
a) 0°
b) 45°
c) tan”1 (1/2)
d) tan”1 (2)
Ans: b
25. If a prismatic member with area of cross-section A is subjected to a tensile load P, then the maximum shear stress and its inclination with the direction of load respectively are
a) P/A and 45°
b) P/2Aand45°
c) P/2A and 60°
d) P/A and 30°
Ans: b