Loading [MathJax]/jax/element/mml/optable/GreekAndCoptic.js

CBSE Questions for Class 11 Engineering Physics Mechanical Properties Of Solids Quiz 14 - MCQExams.com

The ice storm in the state of Jammu strained many wires to the breaking point. In a particular situation, the transmission towers are separated by 500 m of wire. The top grounding wire 15o from horizontal at the towers, and has a diameter of 1.5cm. The steel wire has a density of 7860 kg m3. When ice (density 900 kg m3) built upon the wire to a diameter 10.0 cm, the wire snapped. What was the breaking stress (force/ unit area) in N m2 in the wire at the breaking point? You may assume the ice has no strength.
  • 7.4 ×107 N m2
  • 4.5 ×108 N m2
  • 2.6 ×106 N m2
  • 1.15 ×107 N m2
A spherical ball contracts in volume by 0.01% when subjected to a normal uniform pressure of 100 atmospheres. The bulk modulus of its material in dynes/cm2 is?
  • 10×1012
  • 100×1012
  • 1×1012
  • 2×10
The length of a wire increases by 8mm when a weight of 5kg is suspended from it. If other things remain the same but the radius of the wire is doubled, what will be the increase in its length?
  • 5mm
  • 2mm
  • 7mm
  • 9mm
A student performs an experiment to determine the Young's modulus of a wire, exactly 2m long, by Searle's method. In a particular reading, the student measures the extension in the length of the wire to be 0.8mm with an uncertainty of 0.05mm at a load of exactly 1.0kg. The student also measures the diameter of the wire to be 0.4mm with an uncertainty of 0.01mm. Take g=9.8ms2 (exact). The Young's modulus obtained from the reading is:
  • (2.0 ˉ+ 0.3)×1011Nm2
  • (2.0 ˉ+ 0.2)×1011Nm2
  • (2.0 ˉ+ 0.1)×1011Nm2
  • (2.0 ˉ+ 0.05)×1011Nm2
When a metal wire is stretched by a load, the fractional change in its volume (ΔVV) is proportional to.
  • Δll
  • (Δll)2
  • Δll
  • None of these
A load is supported using three wires of same cross section area as shown. Then for :
List - IList - II
pEqual tensile stress in all wires1Y2 = 2Y1
qEqual tension in all wires2Y2 = 4Y1
rEqual elastic potential energy in all wires
3Y2 = 8Y1
sEqual elastic potential energy per unit volume in all wires4Y2 = 16Y1


1025666_b24959ad3509460ea714a5b458941b8f.png
  • P- 2, Q- 3, R- 1, S- 4
  • P- 1, Q- 4, R- 2, S- 3
  • P- 3, Q- 2, R- 4, S- 1
  • P- 2, Q- 2, R- 3, S- 4
A uniform wire of length L and radius r is twisted by an angle α. If modulus of rigidity of the wire is η, then the elastic potential energy stored in wire, is 
  • πηr4α2L2
  • πηr4α24L
  • πηr4α4L2
  • πηr4α22L
A mass m is hanging from a wire of cross sectional are A and length L. Y is young's modulus of wire. An external force F is applied on he wire which is then slowly further pulled down by x from its equilibrium position. Find the work done by the force F that the wire exerts on the mass:
  • mgx+YA2L(x)2
  • mgx+YA(x)2L
  • mgx2+YA(x)2L
  • mgΔx2+YA(Δx)22L
Two wires of the same radius and material and having length in the ratio 8.9:7.6 are stretched by the same force. The strains produced in the two cases will be in the ratio:
  • 1:1
  • 8.9:1
  • 1:7.6
  • 1:3.2
Breaking stress for steel is F/A, where A is the area of cross-section of steel wire. A body of mass M is tied at the end of the steel wire of length L and whirled in a horizontal circle. The maximum number of revolution it can make per second is:
  • FA4π2ML
  • F4π2MLA
  • F4π2ML
  • 4π2MLA
 A mild steel wire of length 2l meter cross-sectional area Am2 is fixed horizontally between two pillars. A small mass m kg is suspended from the mid point of the wire. If extension in wire are within elastic limit. Then depression at the mid point of wire will be
  • (MgYA)1/3
  • (MgIA)1/3
  • (Mgl3YA)1/3
  • Mg2YA
Two wires of equal length and cross-section are suspended as shown in figure. Their young's modulus are Y1 and Y2 respectively. Their equivalent young's modulus of elasticity is :
1108292_55643b56e1194ffc9f914c6400dc0b5d.PNG
  • Y1+Y2
  • Y1+Y22
  • Y1Y2
  • Y1Y2
The Young's modulus of brass and steel are respectively 1.0×1010N/m2 and 2×1010N/m2. A brass wire and a steel wire of the same length are extended by 1 mm under the same force, the radii of brass and steel wires are RB and RS respectively. Then 
  • RS=2RB
  • RS=RB2
  • RS=4RB
  • RS=RB4
A solid sphere of radius R made of a material of bulk modulus B surrounded by a liquid in a cylindrical container.A massless  piston of area A floats on the surface of the liquid. Find the fractional decreases in the radius of the sphere (dRR) when a mass M is placed on the piston to compress the liquid:
  • (3MgAB)
  • (2MgAB)
  • (Mg3AB)
  • (Mg2AB)
A uniform rod of length L, has a mass per unit length λ and area of cross-section A. The elongation in the rod is l due to its own weight, if it is suspended from the ceiling of a room.The Young's modulus of the rod is 
  • λgL22Al
  • 3λgL2Al
  • 2λgLAl
  • λgL2Al
If δ is the depression produced in beam of length L, breath b and thickness d, when a load is placed at the mid point, then
  • δL3
  • δ1b3
  • δ1d
  • All of these
A metallic ring of radius 2cm and cross sectional area 4cm2 is fitted into a wooden circular disc of radius 4cm.If the Young's module of the material of the ring is 2×1011N/m2, the metal ring expand is:
  • 2×107N
  • 8×107N
  • 4×107N
  • 6×107N
The normal density of mercury is p and its bulk modulus is B. The increase in density of gold when a pressure p is applied uniformly on all sides is:
  • pPB
  • 2ppB
  • pBB
  • Bpp
The substances having very short plastic region are
  • Ductile
  • Brittle
  • Malleable
  • All of these
A neutron moving with a velocity v and kinetic energy E collides perfectly elastically head on with the nucleus of an atom of mass number A at rest. The energy received by the nucleus and the total energy of the system are related by
  • 4A(A+1)2
  • (A1A+1)2
  • (A+1)4A2
  • (A+1A1)2
When a 20g mass hangs attached to one end of a light spring of length 10cm, the spring stretches by 2cm. The mass is pulled down unitl the total length of the spring is 14cm. The elastic energy, in Joule stored in the spring is -
  • 4×102
  • 4×103
  • 8×102
  • 8×103
One end of a uniform rod of mass M and cross-sectional area A is suspended from the other end. The stress at the mid-point of the rod will be :
  • 2MgA
  • 3Mg2A
  • MgA
  • Zero
A force F is applied along a rod of transverse sectional area A. The normal stress to a sectior PQ inclined θ to transverse section will be maximum for θ (in degree) is 
1125154_80de3fc4109b43bfa7d8056376bc8ed7.png
  • 0
  • 30
  • 45
  • 90
A steel wire of length 1.5 m and area of cross section 1.5 mm2 is stretched by 1.5 cm. then the work done per unit volume. (Y=2×1011Nm2).
  • 1×107J/m3
  • 2×107J/m3
  • 3×107J/m3
  • 4×107J/m3

A thick rope of rubber of density 1.5×103kg/m3 and Young's modulus 5×106N/m2 , 8m length is hung from the ceiling of a room , the increases in its length due to its own weight is :

 (g=10m/s2)

  • 9.6×10 - 2m
  • 19.2×10 - 7m
  • 9.6×10 - 7m
  • 9.6m
The average density of Earth's crust 10km benearth the surface is 2.7gm/cm3. The speed of longitudinal seismic waves at that depth is 5.4km/s. The bulk modulus of Earth's crustconsidering its behaviour aas fluid at that depth is:
  • 7.9×1010Pa
  • 5.6×1010Pa
  • 7.9×107Pa
  • 1.46×107Pa
Two wires of the same material (young's modules Y) and same length L but radii R and 2R respectively are joined end to end and a weight W is suspended from the combination as shown in the figure. the elastic potential energy in the system in equilibrium is 
1152580_b60fcab9ae9c4125946cf246ed0041fe.png
  • 3W2L4πR2Y
  • 3W2L8πR2Y
  • 5W2L8πR2Y
  • W2LπR2Y
What is the approximate change in density of water in a lake at a depth of 400 m below the surface? The density of water at the surface is 1030 kg/m3 and bulk modulus of water is 2×109N/m3
  • 4 kg/m3
  • 2 kg/m3
  • 6 kg/m3
  • 8 kg/m3
Assume that a block of very low shear modulus is fixed on an inclined place as shown. Due to elastic forces it will deform. What will be the shape of the block?
1177024_192019c022d5496c9a57b27b6f90facd.png
  • none 
  • all of these
A material has normal density ρ and bulk modulus B. The increase in the density of the material, when it is subjected to an external pressure P from all sides is :
  • PρB
  • BPρ
  • PρB
  • BρP
A horizontal rod is supported at both ends and loaded at the middle. It L and Y are length and Young's modulus respectively, then depression at the middle is directly proportional to
  • L
  • L2
  • Y
  • 1Y
A-3 Two wire of equal length and cross-sectional area suspended as shown in figure. Their Young's modulus are Y1andY2 respectively. The equivelent Young's modulus will be 
1232407_a5287fe924f64bf4b16f4b3a61ca4d35.png
  • Y1+Y2
  • Y1+Y22
  • Y1Y2Y1+Y2
  • Y1Y2
If a rubber ball is taken down to a 100 m deep lake, its volume decreases by 0.1%. If g=10m/s2 then the bulk modulus of elasticity for rubber, in N/m2, is 
  • 108
  • 109
  • 1011
  • 1010
A 2\ m long light metal rod AB is suspended from the ceiling horizontally by means of two vertical wires of equal length, tied to its ends. One wire is of brass and has cross-section of 0.2 \times 10 ^ { - 4 }\ m ^ { 2 } and the other is of steel with 0.1 \times 10 ^ { 4 }\ m^2 cross-section. In order to have equal stresses in the two wires, a weight should be hung from the rod from end A a distance of
1217679_f4c4b7c328074b3aa85bbb374847dd5d.png
  • 66.6\ cm
  • 133\ cm
  • 44.4\ cm
  • 155.6\ cm
A particle of mass m is moving with constant speed v in a circular path on a smooth horizontal plane by a spring as shown. If the natural length of the spring is l _ 0 and stiffness of the spring is k, the elongation of the spring is :
1210187_c224823f775c44c897fb679e64ba64e3.png
  • \dfrac { { k }^{ 2 }{ l }_{ 0 }^{ 2 }+4{ mv }^{ 2 }{ k }-{ kl }_{ 0 } }{ 2k }
  • \dfrac { \sqrt { { k }^{ 2 }{ l }_{ 0 }^{ 2 }+{ 4mv }^{ 2 }k } -{ kl }_{ 0 } }{ 2k }
  • \dfrac { \sqrt { { k }^{ 2 }{ l }_{ 0 }^{ 2 }+{ 4mv }^{ 2 }k-{ kl }_{ 0 } } }{ 2k }
  • \dfrac { \sqrt { { k }^{ 2 }{ l }_{ 0 }^{ 2 }+{ 4mv }^{ 2 }k } +{ kl }_{ 0 } }{ 2k }
Two wires of the same material (young's modules Y) and same length L but radii R and 2R respectively are joined end to end and a weight W is suspended from the combination as shown in the figure. the elastic potential energy in the system in equilibrium is 
  • \dfrac { 3{ W }^{ 2 }L }{ 4\pi { R }^{ 2 }Y }
  • \dfrac { 3{ W }^{ 2 }L }{ 8\pi { R }^{ 2 }Y }
  • \dfrac { 5{ W }^{ 2 }L }{ 8\pi { R }^{ 2 }Y }
  • \dfrac { { W }^{ 2 }L }{ \pi { R }^{ 2 }Y }
The intensity at the maximum in a Young's double slit experiment is { I }_{ 0 }. Distance between two slits is d=5\lambda , where \lambda is the wavelength of light used in the experiment. What will be the intensity in front of one of the slits on the screen at a distance D = 10 d ?
  • { I }_{ 0 }
  • \cfrac { { I }_{ 0 } }{ 4 }
  • \cfrac { 3 }{ 4 } { I }_{ 0 }
  • \cfrac { { I }_{ 0 } }{ 2 }
Find the stress in CD.
Area of CD = 2\ m^2
1217670_d775744f8703447cacd5a75c30f62fbe.png
  • 15\ N/m^2
  • 5\ N/m^2
  • 20\ N/m^2
  • None \ of  \ these
The increase in length of a wire is \Delta \ell when force 'F' is applied on one end of the wire with its other end fixed with a rigid support. Ratio of energy stored in the wire to the work done in stretching it is
  • 1:1
  • 2:1
  • 1:2
  • 1:4
A uniform steel wire hangs from the ceiling and elongates due to its own weight. The ratio of elongation of the lower half of wire is 
  • 4:1
  • 3:1
  • 3:2
  • 1:1
A wire is stretched by 0.01 m by a certain force 'F' another wire of  same material whose diameter and lengths are double to original wire is stretched b the same force then its elongation will be-
  • 0.005 m
  • 0.01m
  • 0.02 m
  • 0.04 m
When a temperature of a gas is 20^0C and pressure is changed from P_1 = 1.01 \times 10^5 Pa to P_2 = 1.165 \times 10^5 Pa then the volume changed by 10%. The bulk modulus is
  • 1.55 \times 10^5 Pa
  • 0.115 \times 10^5 Pa
  • 1.4 \times 10^5 Pa
  • 1.01 \times 10^5 Pa
A wire of length 1\, m and its area of cross-section is 1\, cm^3. The Young's modulus of the wire is 10^{11}\, Nm^{-2}. Two forces each equal to F are applied on its two ends in the opposite directions. If the change in length be 1\, mm, what is the value of F?
  • 0.5 \times 10^4 \, N
  • 10^4 \, N
  • 2 \times 10^4 \, N
  • None of these

A massless and thin string is wrapped several times around a disc kept on a rough horizontal surface. A boy standing at a distance 'd' for the cylinder holds free end of the string pulls the cylinder towards him. If there is no slipping, length of the string passed through the hand of the boy while the cylinder reaches his hands is

  • d
  • 2d
  • 3d
  • 4d
One end of a uniform wire of length Land of weight Wis attached rigidly to a point in the roof and a weight W_1, is suspended from its lower end. If A is the area of cross section of the wire, the stress in the wire at a height \cfrac{6L}{8} from its lower end is
  • \cfrac{W_1}{A}
  • \cfrac{W_1+(W/4)}{A}
  • \cfrac{W_1+(3W/4)}{A}
  • \cfrac{W_1+W}{A}
Y,K,n represent the Young's modulus, bulk modulus and rigidity modulus of a body respectively. If rigidity modulus is twice the bulk modulus, then 
  • Y=5K/18
  • Y=5 n/9
  • Y=9K/5
  • Y=18K/5

 An elastic string carrying a body of mass 'm' extends by 'e'. The body rotates in a vertical circle with critical velocity. The extension in the string at the lowest position is 

  • 2 e
  • 4 e
  • 6 e
  • 8 e
In a Young's double slit experiment with sodium light, slits are 0.589 m apart. The angular separation of the maximum from the central maximum will be (given \lambda =589nm,):
  • { sin }^{ -1 }\left( { 0.33\times 10 }^{ 8 } \right)
  • { sin }^{ -1 }\left( { 0.33\times 10 }^{ 6 } \right)
  • { sin }^{ -1 }\left( { 3\times 10 }^{ 8 } \right)
  • { sin }^{ -1 }\left( { 3\times 10 }^{ -6 } \right)
A rod of length L with square cross-section (a \times a) is bend to form a circular ring.
Then the value of stress developed at points E and F respectively, (Y is Young's modulus of metal rod)

1324119_d9d5c1c4d031457889db9e2ccc3ec7f0.PNG
  • Zero in both
  • \dfrac{2\pi a Y}{L} compression, \dfrac{2\pi a Y}{L} tension
  • \dfrac{\pi a Y}{L} compression, \dfrac{\pi a Y}{L} tension
  • 2\dfrac{\pi a Y}{L} compression in both.
A uniform slender rod of length L, cross-sectional area A and Young's modulus Y is acted upon by the forces shown in the figure. The elongation of the rod is
1327387_267085780dfb4ca1b16dadbb36600422.png
  • \dfrac{3FL}{5AY}
  • \dfrac{2FL}{5AY}
  • \dfrac{3FL}{8AY}
  • \dfrac{8FL}{3AY}
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Class 11 Engineering Physics Quiz Questions and Answers