870+ Strength of Materials Solved MCQs

1.

Hooke's law holds good up to..

A. yield point
B. proportional limit
C. plastic limit
D. breaking point
Answer» B. proportional limit
2.

The ratio of linear stress to linear strain is called as

A. modulus of elasticity
B. modulus of rigidity
C. bulk modulus
D. poisson's ratio
Answer» A. modulus of elasticity
3.

The modulus of elasticity for mild steel is approximately equal to

A. 80 kn/mm2
B. 100 kn/mm2
C. 110 kn/mm2
D. 210 kn/mm2
Answer» D. 210 kn/mm2
4.

When the material is loaded with elastic limit , then the stress is ……. to strain.

A. equal
B. directly proportional
C. inversely proportional
D. not equal
Answer» B. directly proportional
5.

The ratio of ultimate tensile stress to the design stress is known as

A. elastic limit
B. strain
C. factor of safety
D. bulk modulus
Answer» C. factor of safety
6.

An aluminum member is designed based on

A. yield stress
B. elastic limit stress
C. proof stress
D. ultimate stress
Answer» A. yield stress
7.

The poisson's ratio for Cast Iron varies from

A. 0.25 to 0.33
B. 0.21 to 0.25
C. 0.23 to 0.27
D. 0.33 to 0.38
Answer» C. 0.23 to 0.27
8.

The Poisson’s ratio for steel varies from

A. 0.21 to 0.25
B. 0.25 to 0.33
C. 0.33 to 0.38
D. 0.38 to 0.45
Answer» B. 0.25 to 0.33
9.

The property of material to absorb shock energy without failure is known as….

A. elasticity
B. toughness
C. stiffness
D. resilience
Answer» B. toughness
10.

Young’s modulus of Elasticity for perfectly rigid body is….

A. zero
B. unity
C. infinity
D. none of these
Answer» C. infinity
11.

The stress is….

A. scalar
B. vector
C. tensor
D. none of the above
Answer» C. tensor
12.

The Poisson’s ratio for perfectly rigid body is

A. 1
B. 0
C. -1
D. 0.5
Answer» B. 0
13.

Shearing strain is represented by………

A. angle of twist
B. angle of shear
C. deforming force
D. deforming torque
Answer» B. angle of shear
14.

Greater the value of modulus of elasticity more…is the material

A. plastic
B. elastic
C. brittle
D. ductile
Answer» B. elastic
15.

Stress does not depand upon

A. applied force
B. area of c/s
C. modulus of elasticity
D. none
Answer» C. modulus of elasticity
16.

stress does not depend upon

A. applied force
B. area of c/s
C. change in length
D. none
Answer» C. change in length
17.

modulus of elasticity for rubber is ……than that for steel.

A. larger than
B. equal to
C. smaller than
D. any of the above
Answer» C. smaller than
18.

Change in length of the rod due to change in temperature depends on…

A. original length
B. change in temperature
C. coefficient of thermal expansion
D. all of above
Answer» D. all of above
19.

The value of K for perfectly rigid body is

A. zero
B. 1
C. -1
D. infinity
Answer» D. infinity
20.

Time dependent permanent deformation is called as

A. plastic deformation
B. elastic deformation
C. creep
D. an elastic deformation
Answer» C. creep
21.

Figure out the odd point in the following

A. proportional limit
B. elastic limit
C. yield point
D. fracture point
Answer» D. fracture point
22.

Engineering stress strain curve and true stress strain curve are equal up to

A. proportional limit
B. elastic limit
C. yield point
D. tensile strength point
Answer» C. yield point
23.

Shape of true stress strain curve of material depends upon

A. strain
B. strain rate
C. temperature
D. all of the above
Answer» D. all of the above
24.

Within elastic limit in a loaded material, stress is

A. inversely proportional to strain
B. directly proportional to strain
C. equal to strain
D. none of the above
Answer» B. directly proportional to strain
25.

The ratio of linear stress to linear strain is known as

A. poisson's ratio
B. bulk modulus
C. modulus of rigidity
D. modulus of elasticity
Answer» D. modulus of elasticity
26.

the ratio of lateral strain to linear strain is known as

A. poisson's ratio
B. bulk modulus
C. modulus of rigidity
D. modulus of elasticity
Answer» A. poisson's ratio
27.

The ratio of shear stress to shear strain is known as

A. poisson's ratio
B. bulk modulus
C. modulus of rigidity
D. modulus of elasticity
Answer» C. modulus of rigidity
28.

The ratio of normal stress of each face of a solid cube to volumetric strain is called

A. poisson's ratio
B. bulk modulus
C. modulus of rigidity
D. modulus of elasticity
Answer» B. bulk modulus
29.

Hooke's law holds good up to

A. proportional limit
B. yield point
C. elastic limit
D. plastic limit
Answer» A. proportional limit
30.

The property of material by virtue of which a body returns to its original shape after removal of load is known as

A. ductility
B. plasticity
C. elasticity
D. resilience
Answer» C. elasticity
31.

The work done in producing strain on a material per unit volume is called

A. resilience
B. ductility
C. elasticity
D. plasticity
Answer» A. resilience
32.

The property of material by virtue of which a material can be beaten into plates is called

A. ductility
B. malleability
C. resilience
D. plasticity
Answer» B. malleability
33.

The Combined effect of external forces acting on body is called

A. stress
B. strain
C. load
D. none
Answer» C. load
34.

………….Load is one which is considered to act at a point.

A. triangular
B. uniformly distributed load
C. point
D. none
Answer» C. point
35.

The internal resistance which the body offers to meet the load or external force is called

A. stress
B. strain
C. pressure
D. none
Answer» A. stress
36.

The Unit of stress in SI unit is

A. mn/mm2
B. kn/mm2
C. n/mm2
D. all of above
Answer» D. all of above
37.

……….represents the resistance developed by a unit area of cross section.

A. unit stress
B. total stress
C. either of above
D. all of above
Answer» A. unit stress
38.

Simple stress is often called

A. direct stress
B. transverse stress
C. total stress
D. any of above
Answer» A. direct stress
39.

The deformation per unit length is called……….

A. strain
B. tensile stress
C. compressive stress
D. shear stress
Answer» A. strain
40.

If L and dL are are length and change in length respectively, then strain is equal to

A. dl/l
B. l/dl
C. lxdl
D. none
Answer» A. dl/l
41.

If V is the volume of a rectangular bar subjected to a three dimensional stress state and the Poisson's ratio for the material is 0.5, the change in volume of the bar will be __ _.

A. v
B. 2v
C. 0.5v
D. 0
Answer» D. 0
42.

For material Poisson’s ratio is 0.25. Relation between E and G will be

A. 0
B. 2g
C. 3g
D. 2.5g
Answer» D. 2.5g
43.

The modulus of elasticity of a material is 210 GPa and its Poisson's ratio is 0.4. The modulus of rigidity of the material is

A. 210
B. 75
C. 350
D. 300
Answer» B. 75
44.

The value of factor of safety is always

A. >1
B. <1
C. =1
D. =0
Answer» A. >1
45.

The value of margin of safety is always

A. >1
B. <1
C. =1
D. >0
Answer» D. >0
46.

If the working load is one third of the ultimate load, the factor of safety is

A. 0.333
B. 3
C. 2
D. 1
Answer» B. 3
47.

If 1 is subtracted from the ratio of yield stress to working stress the quantity obtained is known as

A. margin of safety
B. f.o.s.
C. modulus of elasticity
D. none of the above
Answer» A. margin of safety
48.

Stress does not depend upon

A. applied force
B. area of c/s
C. change in length
D. none of the above
Answer» C. change in length
49.

Stress does not depend upon

A. applied force
B. area of c/s
C. modulus of elasticity
D. none of the above
Answer» C. modulus of elasticity
50.

A metal plate of length L and width b has a circle drawn on it. If it is subjected to a compressive stress acting along its width, the circle will

A. remain circle of same radius
B. become ellipse with major axis along its width
C. become ellipse with major axis along its length
D. become circle of smaller radius
Answer» C. become ellipse with major axis along its length
51.

If D is the diameter of the sphere, then volumetric strain is equal to

A. two times the strain of diameter
B. 1.5 times the strain of diameter
C. three times the strain of diameter
D. the strain of diameter
Answer» C. three times the strain of diameter
52.

If L be the length and D be the diameter of cylindrical rod, then volumetric strain of the rod is equal to

A. strain of length plus strain of diameter
B. strain of diameter
C. strain of length plus twice the strain of diameter
D. strain of length
Answer» C. strain of length plus twice the strain of diameter
53.

the extension per unit length of the rod due to suddenly applied load as compare to same load gradually applied to same rod is

A. same
B. double
C. three times
D. half
Answer» B. double
54.

The tensile force at a distance y from support in a vertical hanging bar of length L whch carries a load P at the bottom is equal to---- where w = weight per unit length

A. p
B. p+wl
C. p+w(l-y)
D. p+wy
Answer» C. p+w(l-y)
55.

Total elongation produced in a bar due to its self weight is given by……….. Where ρ is the density of material in kg/m3

A. 9.81ρl2/e
B. 9.81ρl2/2e
C. 9.81ρl/e
D. 9.81ρ2l/2e
Answer» B. 9.81ρl2/2e
56.

The elongation of circular tapered rod is given by…………. Where P=axial pull and d1, d2= diameters at two ends.

A. 4pl/πed1d2
B. 2pl/πed1d2
C. 4pl/ed1d2
D. 4p2l/ed1d2
Answer» A. 4pl/πed1d2
57.

If a bar of length L m extends by l mm under load W, the strain is

A. 1000 l/l
B. l/l
C. 0.001 l/l
D. none of the above
Answer» C. 0.001 l/l
58.

Four wires of same material are applied the same load. In which of the following cases, the elongation will be maximum (length, diameter)?

A. 2m, 1mm
B. 4m, 2mm
C. 8m, 4mm
D. 12m, 6mm
Answer» A. 2m, 1mm
59.

If ES = 3 EA , the stress in steel of a composite bar made of aluminium and steel strips each having a cross sectional area of 300 mm2 and subjected to an axial load of 12 kN

A. 10mpa
B. 20mpa
C. 30mpa
D. 40mpa
Answer» C. 30mpa
60.

The modulus of rigidity in terms of modulus of elasticity is given by

A. e/2(1-γ)
B. e/2(1+γ)
C. 2e/(1-γ)
D. 2e/(1+γ)
Answer» B. e/2(1+γ)
61.

The modulus of elasticity in terms of bulk modulus is given by

A. 3k/(1+2γ)
B. 3k(1+2γ)
C. 3k/(1-2γ)
D. 3k(1-2γ)
Answer» D. 3k(1-2γ)
62.

The ratio of Young's modulus and bulk modulus is given by

A. 3/(1+2γ)
B. 3(1+2γ)
C. 3/(1-2γ)
D. 3(1-2γ)
Answer» D. 3(1-2γ)
63.

The modulus of elasticity in terms of bulk modulus and modulus of rigidity is given by

A. 9kg/(3k+g)
B. 9kg/(k+3g)
C. (3k+g)/9kg
D. (k+3g)/9kg
Answer» A. 9kg/(3k+g)
64.

For a Poisson's ratio of 0.4 for a material the ratio of shear modulus of elasticity to modulus of rigidity is

A. 14/5
B. 5/7
C. 7/5
D. 5/14
Answer» D. 5/14
65.

A material has modulus of rigidity equal to 0.4x105 N/mm2 and Bulk modulus equal to 0.95 x105 N/mm2 The Young’s modulus value in GPa is..

A. 115
B. 105
C. 145
D. 175
Answer» B. 105
66.

A bar of 30 mm diameter is subjected to an axial force 280 KN length of bar is 400 m and E= 200GPa. Determine volumetric strain if m=4.

A. 1.46x10-3
B. 9.9 x 10-4
C. 2.9 x 10-3
D. 1.48 x 10-4
Answer» B. 9.9 x 10-4
67.

A rail 20 m long is prevented from expansion at both end . If the temperature is raised by 30 0C, Stress induced in rail is.. E=200 Gpa,α =12x10-6/°C

A. 24 mpa
B. 48mpa
C. 72mpa
D. 94mpa
Answer» C. 72mpa
68.

A tensile material is having Young’s modulus 2.1 x105 N/mm2 and modulus of Rigidity is 0.82 x105 N/mm2. The value of Bulk Modulus is ..

A. 1.4 x105 n/mm2
B. 1.6 x105 n/mm2
C. 1.81 x105 n/mm2
D. 1.5 x105 n/mm2
Answer» B. 1.6 x105 n/mm2
69.

A steel rod of length is manufactured at a temperature 200C and its temperature increases upto 1350C.What are thermal stresses induced? E=200Gpa,α=12*10-6/0C

A. 312mpa
B. 310mpa
C. 320mpa
D. 276mpa
Answer» D. 276mpa
70.

A steel rod of 3m is manufactured at 250C the temperature of rod is increases to 1250C. If free expansion is 3.6mm, what is the temperature stresses produced if 1.5mm expansion is permitted?

A. 100mpa
B. 200mpa
C. 150mpa
D. 140mpa
Answer» D. 140mpa
71.

A steel rod of 3m length is manufactured at 250C the temperature of this rod increases to 1250C. What is the free expansion? Take E=200Gpa, α=12*10-6/0C,diameter=12mm

A. 3.2mm
B. 2.6mm
C. 4mm
D. 3.6mm
Answer» D. 3.6mm
72.

A steel tube (E = 200 GPa) has an internal diameter of 40 mm thickness 10 mm and a length of 2 m. If it is subjected to an axial pull of 80 kN, the stress in the tube will be __ _MPa.

A. 28.3
B. 50.13
C. 84.88
D. 113.18
Answer» B. 50.13
73.

A steel tube (E= 200Gpa) has an internal diameter of 40 mm, thickness 10 mm and a length of 2 m. If it is subjected to an axial pull of 80 kN, the change in length of the tube will be __ _mm.

A. 0.283
B. 0.5
C. 0.85
D. 0.113
Answer» B. 0.5
74.

The axial force in the portion AB of the member shown in Fig. 1.1 is kN.

A. 50
B. -50
C. 40
D. -40
Answer» A. 50
75.

If the member shown in Fig. 1.1 has a square cross section of 25 mm
25 mm and E = 200 GPa, the change in length of portion AB is
             mm.

A. 0.24
B. -0.24
C. 0.32
D. -0.32
Answer» A. 0.24
76.

The axial force in the portion BC of the member shown in Fig. 1.1 is kN.

A. 50
B. -50
C. 40
D. -40
Answer» D. -40
77.

If the member shown in Fig. 1.1 has a
square cross section of 25 mm 25 mm and E = 200 GPa, the change in length of portion CD is ------mm

A. 0.16
B. -0.16
C. 0.24
D. -0.24
Answer» B. -0.16
78.

The axially loaded composite rod shown in Fig. 1.2 has a uniform cross- sectional area of 500 mm 2 . The modulii of elasticity are Est = 200 GPa, Eal = 70 GPa and Ecu = 120 GPa. The change in length of CD is mm.

A. 0.15
B. -0.15
C. 0.24
D. -0.24
Answer» A. 0.15
79.

The axially loaded composite rod shown in Fig. 1.2 has a uniform cross- sectional area of 500 mm 2 . The modulii of elasticity are Est = 200 GPa, Eal = 70 GPa and Ecu = 120 GPa. The change in length of the composite rod is mm.

A. 0.95
B. -0.95
C. 0.5
D. -0.5
Answer» B. -0.95
80.

For the stepped rod shown in Fig. 1.3, the stress is maximum in .

A. aluminum
B. copper
C. steel
D. none of these
Answer» C. steel
81.

For the stepped rod shown in Fig. 1.3,the in .

A. aluminum
B. copper
C. steel
D. none of these
Answer» A. aluminum
82.

A steel bar ABC (E = 200 GPa) is 1 m long. For AB = 0.7 m, it has cross section P area of 500 mm2 and for BC = 0.3 m the cross section area is 400 mm2. The bar is subjected to an axial pull of 100 kN. The stress is maximum in ___ _

A. ab
B. bc
C. same throughout
D. none of these
Answer» B. bc
83.

A stepped bar of steel consists of a pmormtion with cross section area 500 mm2 connected to a portion with cross section area 1000 2. Each portion has a length of 1 m. The modulus of elasticity of steel is
200 GPa. The maximum elongation of the bar by applying an axial tensile force at the ends without exceeding a stress of 100 MPa is
   mm.

A. 0.5
B. 0.75
C. 0.1
D. 0.15
Answer» B. 0.75
84.

The change in length of a rod of uniform circular cross section was found to be 2 mm for some applied force. The change in length of a rod of the same material and length but of half the diameter subjected to the same force will be Mm

A. 1
B. 2
C. 0.5
D. 4
Answer» D. 4
85.

A strip of steel (E = 200 GPa, 0.25) has a length of 1 m, width of
200 mm and thickness of 10 mm. A line of length 1 m is drawn parallel to its length on one of its side surfaces. When the strip is subjected to an axial tensile force of
100 kN, the length of the line will be
                 mm.

A. 1000
B. 1000.25
C. 999.25
D. 0.25
Answer» B. 1000.25
86.

The change in length of a rod of uniform cross section was found to be 2 mm for some applied force. The change in length of a rod of the same material and length but of twice the cross section area subjected to the same force will be__ mm.

A. 1
B. 2
C. 0.5
D. 4
Answer» A. 1
87.

Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces with magnitudes in the ratio 2 : 1. The stresses induced in the two rods will be in the ratio ____ _.

A. 1 : 2
B. 2 : 1
C. 1 : 1
D. 4 : 1
Answer» D. 4 : 1
88.

Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces with magnitudes in the ratio 1 : 2. The stresses induced in the two rods will be in the ratio ____ _.

A. 1:1
B. 1:2
C. 1:1
D. 4:1
Answer» C. 1:1
89.

Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces of the same magnitude. The stresses induced in the two rods will be in the ratio __ _ .

A. 1 : 2
B. 2 : 1
C. 1 : 1
D. 4 : 1
Answer» B. 2 : 1
90.

If an axial force of 15 kN is applied to a rod of 25 mm diameter, length 300 mm, the change in length of the rod was observed to be 0.045 mm. The modulus of elasticity of the material is 200 GPa. The strain in the rod will be ____ _.

A. 1.5
B. 1.5*10-4
C. 1.33*10-3
D. 0.0455
Answer» B. 1.5*10-4
91.

If an axial force of 1 kN is applied to a rod of 100 mm cross section area produces change in length of 1 mm over a length of 12 m, the modulus of elasticity of the material will be---------

A. 120mpa
B. 10gpa
C. 12gpa
D. 120gpa
Answer» D. 120gpa
92.

If an axial force of 1 kN is applied to a rod of 100 mm2 cross section area, length 5 m and the modulus of elasticity of the material is 100 GPa, the change in length of the rod will be ___ .

A. 1mm
B. 1.2mm
C. 0.5mm
D. 0.25mm
Answer» C. 0.5mm
93.

The longitudinal stress developed in a rod of cross section area 50 mm2 is 100 MPa. The force acting along its axis is -------

A. 2n
B. 2.5kn
C. 5n
D. 5.5kn
Answer» D. 5.5kn
94.

If an axial force of 1 kN is applied to a steel rod of 100 mm2 cross section area, the stress in it will be ___ .

A. 10mpa
B. 10gpa
C. 1mpa
D. 1gpa
Answer» A. 10mpa
95.

Two equal and opposite forces of magnitude 10 kN are applied at the ends of a steel wire to increase its length. The internal force in the wire will be-----KN

A. 0
B. 10
C. 20
D. 15
Answer» B. 10
96.

The value of factor of safety is always __ _.

A. >1
B. <1
C. =1
D. =0
Answer» A. >1
97.

The value of margin of safety is always __ _.

A. >1
B. <1
C. =1
D. =0
Answer» D. =0
98.

The radius of wire stretched by a load is doubled, then its Modulus of elasticity will be..

A. doubled
B. halved
C. becomes 4 times
D. unaffected
Answer» D. unaffected
99.

The factor of safety depends on
i)Magnitude of external force
ii) Properties of material
iii) Dimension of the component
iv) All of the above

A. i) and ii)
B. ii) and iii)
C. i) , ii) and iii)
D. iv
Answer» D. iv
100.

The thermal stress is given by where α = coeffeicient of linear expansion T = Rise in temperature

A. eαt
B. et/α
C. eα/t
D. 1/eαt
Answer» A. eαt
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