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CBSE Questions for Class 11 Engineering Physics Mechanical Properties Of Solids Quiz 2 - MCQExams.com

Young's modulus of Perfectly elastic body is
  • Finite value
  • Zero
  • One
  • Infinite value
A wire whose cross-sectional area is 4 mm2 is stretched by 0.1 mm by a certain load. If a similar wire of double the area of cross-section is under the same load, then the elongation would be
  • 0.5 mm
  • 0.05 mm
  • 0.005 mm
  • 5 mm
The force required to double the length of the steel wire of area of cross section 5×105m2(Y=20×1010Pa) in N is:
  • 1017
  • 1016
  • 107
  • 1015
Bulk modulus was first defined by

  • Young
  • Bulk
  • Maxwell
  • None of the above
The only elastic modulus that applies to fluids is

  • Young's Modulus
  • Shear Modulus
  • Modulus of rigidity
  • Bulk modulus
Minimum and maximum values of Poisson’s ratio for a metal lies between
  • to +
  • 0 to 1
  • to 1
  • 0 to 0.5
Ratio of transverse to axial strain is 
  • Toricelli ratio
  • Poisson's ratio
  • Stoke's ratio
  • Bernoulli's ratio
The modulus of elasticity is dimensionally equivalent to
  • Stress
  • Surface tension
  • Strain
  • Coefficient of viscosity
A wire elongates by 1mm when a load W is hung from it. If the wire goes over a pulley and the two weights W, each are hung at the two ends, then the elongation of the wire will be:
  • 0.5mm
  • 1mm
  • 2mm
  • 4mm
An iron bar of length L, cross-section A and Young's modulus Y is pulled by a force F from ends so as to produce an elongation l. Which of the following statements is correct ?
  • l1L
  • lA
  • l1A
  • lY
A wire of length L and radius r fixed at one end and a force F applied to the other end produces and extension l . The extension produced in another wire of the same material of length 2Land radius 2r by a force 2 F is:
  • l
  • 2l
  • l2
  • 4l
Elongation of a wire under its own weight is independent of :
  • Length
  • Area of cross section
  • Density
  • Young's modulus
Assertion (A): Stress is restoring force per unit area.
Reason (R) : Interatomic forces in solids are responsible for the property of elasticity
  • Both Assertion and Reason are true and the reason is correct explanation of the assertion
  • Both Assertion and Reason are true, but reason is not correct explanation of the assertion
  • Assertion is true, but the Reason is false
  • Assertion is false, but the reason is true
If stress is numerically equal to young's modulus,the elongation will be
  • 1/4 the original length
  • 1/2 the original length
  • equal to the original length
  • Twice the original length
A metal string is fixed between rigid supports. It is initially at negligible tension. Its Young's modulus is Y, density is ρ  and coefficient of linear expansion is α. It is now cooled through a temperature t, transverse waves will move along it with a speed of :
  • Yαtρ
  • Yαtρ
  • αYtρ
  • tρYα
Three wires A, B, C made of different materials elongated by 1.5, 2.5, 3.5 mm, under a load of 5kg. If the diameters of the wires are the same,the most elastic material is that of
  • A
  • B
  • C
  • All
Consider the following two statements A and B and identify the correct answer.
A) When the length of a wire is doubled, the Young's modulus of the wire is also doubled
B) For elastic bodies Poisson's ratio is + Ve and for inelastic bodies Poissons ratio is -Ve
  • Both A & B are true
  • A is true but B is false
  • A is true but B is true
  • Both A & B are false
Consider the following two statements A and B and identify the correct answer.
A) The bulk modulus for an incompressible liquid is infinite.
B) Young's modulus increases with raise of temperature.
  • Both A & B are true
  • A is true but B is false
  • Both A & B are false
  • A is false but B is true
Consider the statements A and B, identify the correct answer given below :
(A) : If the volume of a body remains unchanged when subjected to tensile strain, the value of poisson's ratio is 1/2.
(B) : Phosper bronze has low Young's modulus and high rigidity modulus. 
  • A and B are correct
  • A and B are wrong
  • A is correct and B is wrong
  • A is wrong and B is right
The stress required to double the length of a wire of Young's modulus E is :
  • 2E
  • E
  • E/2
  • 3E
The graph shows the behaviour of a steel wire in the region for which the wire obeys Hooke's law.The graph is a part of a parabola. The variables x and y might represent.
21339.png
  • x = stress ; y = strain
  • x = strain ; y = stress
  • x = strain ; y = elastic energy
  • x = elastic energy ; y = strain
Assertion (A) : Lead is more elastic than rubber.
Reason (R) : If the same load is attached to lead and rubber wires of the same cross-sectional area, the strain of lead is very much less than that of rubber.
  • Both assertion and reason are true and the reason is correct explanation of the assertion
  • Both assertion and reason are true, but reason is not correct explanation of the assertion
  • Assertion is true, but the reason is false
  • Assertion is false, but the reason is true
Three wires A,B, C made of the same material and radius have different lengths. The graphs in the figure shows the elongation-load variation. The longest wire is:
21328_837a9f075083411395cab7f0e653484a.png
  • A
  • B
  • C
  • All
Consider the following two statements A and B and identify the correct answer .
A) A metal wire held vertically is longer than when it placed on a horizontal table.
B) Due to its own weight, some elongation is produced when it is held vertically.
  • Both A & B are true
  • A is false but B is true
  • A is true but B is false
  • Both A & B are false
A uniform heavy rod of length L and area of cross-section area A is hanging from a fixed support. If Young's modulus of the material of the rod is Y, then the increase in the length of the rod is (ρ is a density of the material of the rod) :
  • L2Y2ρg
  • L2ρg2Y
  • L2g2Yρ
  • L2g3Yρ
A 20kg load is suspended by a wire of cross section 0.4mm2. The stress produced in N/m2 is :
  • 4.9 x 106
  • 4.9 x 108
  • 49 x 108
  • 2.45 x 106
The length of a wire under stress changes by 0.01%. The strain produced is
  • 104
  • 0.01
  • 1
  • 104
A wire of length 'l' and radius 'r' is clamped rigidly at one end. When the other end of the wire is pulled by a force 'F', its length increases by x. Another wire of same material of length '2l' and radius 2r' is pulled by a force '2F, the increase in its length will be :
  • x
  • 2x
  • x/2
  • 4x
The length of a wire is 4m. Its length is increased by 2mm when a force acts on it. The strain is:
  • 0.5 x 103
  • 5 x 103
  • 2 x 103
  • 0.05
Four wires made of same materials are stretched by the same load. Their dimensions are given below. The one which elongates more is ?
  • Wire of length 1 m and diameter 1 mm
  • Length 2m, diameter 2 mm
  • Length 3m, diameter 3 mm
  • Length 0.5m, diameter 0.5mm
A steel wire of 2mm in diameter is stretched by applying a force of 72N. Stress in the wire is
  • 2.29×107 N/m2

  • 1.17×107 N/m2

  • 3.6×107 N/m2

  • 0.8×107 N/m2
The lengths of two wires of the same material and diameter are 100cm and 125cm. If same force is applied on them, the elongation in the first wire is 4mm. The elongation in the second wire (in mm) is
  • 4
  • 5
  • 0.8
  • 1.25
A force of 30N acts on a rod of area of cross section 5 x 106 m2. The stress produced in dyne/cm2 is :
  • 6×106
  • 6×107
  • 6×105
  • 0.16×106
The force required to double the length of a steel wire of area of cross-section 5×105m2 (in N) is :
(Y=20×1010Pa)
  • 107
  • 106
  • 107
  • 105
The length of two wires are in the ratio 3:4.Ratio of the diameters is 1:2; young's modulus of the wires are in the ratio 3:2; If they are subjected to same tensile force, the ratio of the elongation produced is
  • 1 :1
  • 1 :2
  • 2 : 3
  • 2 : 1
A solid sphere hung at the lower end of a wire is suspended from a fixed point so as to give an elongation of 0.4mm. When the first solid sphere is replaced by another one made of same material but twice the radius, the new elongation is
  • 0.8mm
  • 1.6mm
  • 3.2mm
  • 1.2mm
The ratio of lengths of two wires made of same material is 2:3. The ratio of their respective longitudinal stress to produce same elongation is
  • 4:9
  • 9:4
  • 2:3
  • 3:2
Ratio of lengths of two brass wires is 3 : 4; their areas of cross section are in the ratio 2:When same force is applied on them, the elongations produced will be in the ratio:
  • 9 : 8
  • 8 : 9
  • 22 :3
  • 1 : 1
The length of a wire of cross-sectional area 1× 106m2 is 10m. The young's modulus of the material of the wire is 25 G.pa. When the wire is subjected to a tensile force of 100N, the elongation produced in mm is:
  • 0.04
  • 0.4
  • 4
  • 40
A steel wire of length 1 m has cross sectional area 1cm2. If young's modulus of steel is 1011N/m2 ,then force required to increase the length of wire by 1 mm will be :
  • 1011N
  • 107N
  • 104N
  • 102N
Two steel wires have equal volumes. Their diameters are in the ratio 2 :When same force is applied on them, the elongation produced will be in the ratio of:
  • 1:8
  • 8:1
  • 1:16
  • 16:1
The elongation produced in a copper wire of length 2m and diameter 3mm, when a force of 30N is applied is [Y=1x1011N.m2]
  • 8.5mm
  • 0.85mm
  • 0.085mm
  • 85mm
The diameters of two steel wires are in the ratio 2:Their lengths are equal. When same force is applied on them, the ratio of the elongation produced is
  • 4:9
  • 9:4
  • 3:2
  • 2:3
A copper wire and a steel wire of radii in the ratio 1:2 lengths in the ratio 2:1 are stretched by the same forces. If young's modulus of copper =1.1×1011N/m2, young's modulus of steel =2×1011N/m2. Ratio of their extensions is :
  • 160:11
  • 16:110
  • 1:61
  • 6:11
The force that must be applied to a steel wire 6m long and diameter 1.6mm to produce an extension of 1mm [y=2.0×1011N.m2] is approximate.
  • 100N
  • 50N
  • 67N
  • 33.5N
A volume of 103m3 is subjected to a pressure of 10 atmospheres. The change in volume is 106m3. Bulk modulus of water is (Atmosphere pressure = 1x105N/m2 ) :
  • 1x109 N / m2
  • 1x1010 N / m2
  • 1x1012 N / m2
  • 1x107 N / m2
Two exactly similar wires of steel (y=20 x 1011dyne/cm2) and copper (y = 12 x 1011 dyne/cm2)are stretched by equal forces. If the total elongation is 1cm, elongation of copper wire is
  • 3/5cm
  • 5/3cm
  • 3/8cm
  • 5/8cm
The radii and Young's modulus of two uniform wires A & B are in the ratio 2: 1 and 1: 2 respectively. Both the wires are subjected to the same longitudinal force. If increase in the length of wire A is 1% . Then the percentage increase in length of wire B is :
  • 1
  • 1.5
  • 2
  • 3
A load of 4.0 kg is suspended from a ceiling through a steel wire of length 20 m and radius 2.0 mm. It is found that the length of the wire increases by 0.031 mm as equilibrium is achieved. If g=3.1 π ms2, the value of young's modulus in Nm2 is
  • 2.0×1012
  • 4.0×1011
  • 2.0×1011
  • 0.02×109
Two wires of equal cross section, but one made up of steel and the other copper, are joined end to end. When the combination is kept under tension, the elongations in the two wires are found to be equal. If Ysteel= 2.0 x 1011Nm2 and  Ycopper= 1.1 x 1011Nm2, the ratio of the lengths of the two wires is :
  • 20:11
  • 11:20
  • 5:4
  • 4:5
0:0:3


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