Processing math: 3%

CBSE Questions for Class 11 Engineering Physics Mechanical Properties Of Solids Quiz 9 - MCQExams.com

Select the correct alternative(s).
  • Elastic forces are always conservative
  • Elastic forces are not always conservative
  • Elastic forces are conservative only when Hooke's law is obeyed
  • Elastic forces may be conservative even when Hooke's law is not obeyed
When the load on a wire is increasing slowly from 2 kg to 4 kg, the elongation increases from 0.6 mm to 1 mm. The work done during this extension of the wire is (g=10m/s2).
  • 14×103J
  • 0.4×103J
  • 8×102J
  • 103J
What is the percentage increase in length of a wire of diamater 2.5 mm, stretched by  a force of 100 Kg wt? Youngs modulus of elasticity of wire =1.25×1011 dyne/cm2
  • 0.16%
  • 0.32%
  • 0.08%
  • 0.12%
A steel wire has length 2.0  m, radius 1 mm and Y=2×1011N/m2 A sphere of mass 1 kg is attached at one end of the wire which is then whirled in a vertical circle with speed 2 rev/sec. Elongation of the wire when mass is at the lowest position. 
  • 1.0 mm
  • 2.0 mm
  • 0.1 mm
  • 0.01 mm
Two copper wires having the length in ratio 4:1 and their radii ratio as 1:4 are stretched by the same force. Then the ratio of the longitudinal strain in the two will be 
  • 1:16
  • 16:1
  • 1:64
  • 64:1
A block of mass of 2kg is attached to one end of a wire of cross sectional area 1mm \,\,\,2 and is. Find the elongation of the wire when the block is at top of the circle (Y=2\times 10^{11}Nm^{-2})
  • 0.2892 mm
  • 0.054 mm
  • 01446 mm
  • 0.0017 mm
Scalar are quantity that are describe by 
  • Direction
  • Magnitude and direction 
  • Magnitude
  • Motion
A wire of density 9\times{10^3}kg/{m^3} is stretched between two clamps 1 m apart and is stretched to an extension of 4.9\times{10^{ - 4}}metre. Young's modulus of material is 9\times{10^{10}}N/{m^2}. Then
  • The lowest frequency of standing wave is 35 Hz
  • The frequency of 1st overtone is 70 Hz
  • The frequency of 1st overtone is 105 Hz
  • The stress in the wire is 4.41\times{10^7}N/{m^2}
A two meter long rod is suspended with the help of two wires of equal length. One wire is of steel and its cross-section is 0.1 cm^{2} and another wire is of brass and its cross-section area is 0.2 cm^{2} . If a load W is suspended from the rod and introduced in both the wires is same then the ratio of tensions in them will be
1030671_51e9441439664f22adb094f9faf1a702.png
  • (a) will depend on the position of W
  • (b) T_{1}/T_{2}=2
  • (c) T_{1}/T_{2}=1
  • (d) T_{1}/T_{2}=0.5
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 dyne {cm}^{-2} is:
  • 10\times {10}^{11}
  • 100\times {10}^{2}
  • 1\times {10}^{11}
  • 2\times {10}^{11}
The length of of a metal wire l when the tension in is 'F' and 'xl' when the tension is 'yF'. Then the natural length of the wire is 
  • \dfrac { \left( x-y \right) l }{ x-1 }
  • \dfrac { \left( y-x \right) l }{ y-1 }
  • \dfrac { \left( x-y \right) l }{ x+1 }
  • \dfrac { \left( y-x \right) l }{ y+1 }
A tungsten wire of length 20 cm is stretched by 0.1 cm. Find the strain on the wire.
  • 0.002
  • 0.005
  • 0.001
  • 0.004
When temperature of a gas is 20^oC and pressure is changed from { P }_{ 1 }=1.0\times { 10 }^{ 5 } Pa to { P }_{ 2 }=1.65\times { 10 }^{ 5 } Pa and the volume is changed by 10%. The bulk modulus is :
  • 1.55\times { 10 }^{ 5 }Pa
  • 1.15\times { 10 }^{ 5 }Pa
  • 1.4\times { 10 }^{ 5 }Pa
  • 1.01\times { 10 }^{ 5 }Pa
A solid cube is subjected to a pressure of \left( 5\times { 10 }^{ 5 }\quad N/{ m }^{ 2 } \right) . Each side of the cube is shortened by then volumetric strain and Bulk modulus of the cube are
  • 0.03,5\times { 10 }^{ 5 }\quad N/{ m }^{ 2 }
  • 0.03,1.67\times { 10 }^{ 7 }\quad N/{ m }^{ 2 }
  • 3,1.67\times { 10 }^{ -7 }\quad N/{ m }^{ 2 }
  • 0.01,1.67\times { 10 }^{ 7 }\quad N/{ m }^{ 2 }
Three wires P,Q and R the same materials and length have radii 0.12cm,0.2cm and 0.3cm respectively. Which wire has the highest value of Young's modules of elasticity ?
  • P
  • Q
  • R
  • All have the same value
The stress required to double the length of wire (or) to produce 100\% longitudinal strain is:
  • Y
  • \cfrac{Y}{2}
  • 2Y
  • 3Y
 A uniform rod of length 60 cm and mass 6kg is acted upon by two forces as shown in the diagram. The force exerted by 45 cm part of the rod on 15 cm part of the rod is 

1069048_d060a9f94f934fcba734703899e8a40e.JPG
  • 9 N
  • 18 N
  • 27 N
  • 30 N
Two wires A and B are identical in shape and size are stretched by same magnitude of force. Then the extensions are found to be 0.2% and 0.3% respectively. Find the rate of their Young's modulii
  • 2 : 3
  • 3 : 2
  • 4 : 9
  • 9 : 4
For a material Y={ 6.6\times 10 }^{ 10 }\ { N/m }^{ 2 } and bulk modulus K{ 11\times 10 }^{ 10 }\ { N/m }^{ 2 }, then its Poisson's ratio is:
  • 0.8
  • 0.35
  • 0.7
  • 0.4
A copper wire and an aluminium wire have lengths in the ratio 3:2, diameters in the ration 2:3 and forces applied in the ration 4:Find the ratio of the increase in the length of the two wires. 
\left( { Y }_{ cu }=1.1\times { 10 }^{ 11 }N{ m }^{ -2 },\quad { Y }_{ Al }=0.70\times { 10 }^{ 11 }N{ m }^{ -2 }\quad  \right)
  • 110:189
  • 180:110
  • 189:110
  • 80:11
In the Searle's method to determine the Young's modulus of a wire, a steel wire of length 156\ cm and diameter 0.054\ cm is taken as experimental wire. The average increase in length for 1.5\ kg\ wt is found to be 0.050\ cm. Then the Young's modulus of the wire is
  • 3.002\times 10^{11}N/m^{2}
  • 1.002\times 10^{11}N/m^{2}
  • 2.002\times 10^{11}N/m^{2}
  • 2.5\times 10^{11}N/m^{2}
Three bars having length l,2l and 3l and area of cross-section A,2A and 3A are joined rigidly and to end. Compound rod is subjected to a stretching force F. The increase in length of rod is (Young's modulles of material is Y and bars are massless)
  • \dfrac {13Fl}{2\ AY}
  • \dfrac {3Fl}{AY}
  • \dfrac {9Fl}{AY}
  • \dfrac {13\ Fl}{AY}
A hydraullic press contains 250 lit of oil. Find the decrease in volume of the oil when its  pressure increases to  10^7 Pa . The bulk modulus of the oil is  K = 5 \times 10^5 Pa
  • - 0.8 lit
  • - 0.5 lit
  • - 0.6 lit
  • - 0.9 lit
The breaking stress of aluminium is 7.5\times 10^{7}Nm^{-2}. The greatest length of aluminium wire that can hang vertically without breaking is(Density of auminium is 2.7\times 10^{3}\ kg\ m^{-3})
  • 283\times 10^{3}\ m
  • 28.3\times 10^{3}\ m
  • 2.83\times 10^{3}\ m
  • 0.283\times 10^{3}\ m
A uniform rod of mass m and length l is rotating with constant angular velocity \omega about an axis which passes through its one end and perpendicular to the length of rod. The area of cross section of the rod is A and its young's modulus is Y. Neglect gravity. The strain at the mid point of the rod is :
  • \dfrac{m\omega^2l}{8AY}
  • \dfrac{3m\omega^2l}{8AY}
  • \dfrac{3m\omega^2l}{4AY}
  • \dfrac{m\omega^2l}{4AY}
The length of a rubber cord is l_1 metres when the tension in it is 4N and l_2 metres when the tension is 5N. then the length in meters when the tension is 9N is
  • 3l_2 +4l_1
  • 3l_2 +2l_1
  • 5l_2 - 4l_1
  • 3l_2 - 2l_1
The extension of wire by application of load is 0.3cm  The extension in a w wire of same material but of double the length and half the radius of cross section by the same load will be in (cm) 
  • 0.3
  • 0.6
  • 0.2
  • 2.4
An aluminium rod has a breaking strain 0.2\%. The minimum cross-sectional area of the rod in m^{2} in order to support a load of 10^{4}N is if (Young's modulus is 7\times 10^{9}Nm^{-2})
  • 1.7\times 10^{-4}
  • 1.7\times 10^{-3}
  • 7.1\times 10^{-4}
  • 1.4\times 10^{-4}
Two wires A and B have young's modulii in the ratio 1:2 and ratio of the lengths is 1:1. under the application of same stress the ratio of elongation is
  • 1:1
  • 1:2
  • 2:1
  • 1:4
A steel wire 2\ m in length is stretched by 1\ mm. The cross-sectional area of the wire is 2\ mm^{2}. If Young's modulus of steel is 2\times 10^{11}\ N/m^{2}, then the elastic potential energy stored in the wire is
  • 0.1\ J
  • 0.2\ J
  • 0.3\ J
  • 0.4\ J
An aluminium wire and a steel wire of the same length and cross-section joined end to end. The composite wire is hung from a rigid support and a load is suspended from the free end. If the increase in the length of t\ h\ c composite wire is 2.7\ mm, then the increase in the length of each wire is (in mm).(Y_{At}=2\times 10^{11}Nm^{-3}, Y_{steel}=7\times 10^{11}Nm^{-2})
  • 1, 7, 1
  • 1.3, 1, 4
  • 1.5, 1, 2
  • 2.1, 1, 0.6
Consider the bar in Fig. Cross-sectional area A_{e} = 1.2 in.^{2}, and Young's modulus E = 30\times 10^{6} psi. If q_{1} = 0.02\ in. and q_{2} = 0.025\ in., determine the following (by hand calculation).
  • The displacement at point P
  • The strain \epsilon and stress \sigma
  • The element stiffness matrix, and
  • The strain energy in the element
The force constant of a wire is k and that of another wire of the same material is 2k. When both the wires are stretched, then work done is
  • W_{2}=1.5W_{1}
  • W_{2}=2W_{1}
  • W_{2}=W_{1}
  • W_{2}=0.5W_{1}
A uniform cubical block is subjected to volumetric compression, which decreases its each side of 2%. The Bulk strain produced in it is:
  • 0.03
  • 0.02
  • 0.06
  • 0.12
There are two wires of same material. their radii and lengths are both in the ratio 1:if the extensions produced are equal, what is the ratio of the loads?
  • 1:2
  • 2:1
  • 1:4
  • 4:1
A thick rope of density \rho and length L is hung from a rigid support. The Young's modulus of the material of rope is Y. The increase in length of the rope due to its own weight is
  • \rho g{L}^{2}/4Y
  • \rho g{L}^{2}/2Y
  • \rho g{L}^{2}/Y
  • \rho gL/Y
When a wire is stretched, its length increases by 0.3% and the diameter decreases by 0.1%. Poisson's ratio of the material of the wire is about
  • 0.03
  • 0.333
  • 0.15
  • 0.015
A steel ring of radius r and cross sectional area A is fitted on to a wooden disc of radius R(R> r). If Young;s modulus be Y, then the force with which the steel ring is expanded, is
  • AY\cfrac{R}{r}
  • AY(\cfrac{R-r}{r})
  • \cfrac{Y}{A}\cfrac{(R-r)}{r}
  • \cfrac{Yr}{AR}
Volume of a liquid when compressed by additional pressure of 10^5 N/m^2 is 196cc and when compressed by a pressure of 1.5 \times 10 ^5 N/m^2, the volume is 194cc. The bulk modulus of the liquid is:
  • 10^5N/m^2
  • 1.5 \times 10^6
  • 5 \times10^5N/m^2
  • 5 \times 10^6N/m^2
The maximum load a wire can withstand without breaking, when its length is reduced to half of its original length, will 
  • be double
  • be half
  • be four times
  • remain same
One end of a uniform wire of length L and of weight W you is attached rigidly see through a point in the roof and weight W1 is suspended from its lower end. If S is true area of cross section of the wire the stress in the wire at a height (3L/4) from its lower end is :
  • [W_1 + (W/4)] / S
  • W_1/S
  • [W_1 + (3W/4)] / S
  • (W_1+W) / S
A uniform rod of length L has a mass per unit length \lambda and area of cross section A. If the Young's modulus of the rod is Y. The elongation in the rod due to its own weight is
  • \dfrac{2\lambda gL^2}{AY}
  • \dfrac{\lambda gL^2}{2AY}
  • \dfrac{\lambda gL^2}{4 AY}
  • \dfrac{\lambda gL^2}{6AY}
The relationship between Young's modulus Y, Bulk modulus K and modulus of rigidity \eta is:-
  • Y = \dfrac{9 \eta K}{3 + k}
  • Y = \dfrac{9 \eta K}{n + 3}
  • Y=\dfrac{9 \eta K}{\eta+3 k}
  • Y = \dfrac{3 \eta K}{9 \eta + k}
Two wires of same material and radius have their lengths in ratio 1:2. If these wires are stretched by the same force, the strain produced in the two wires will be in the ratio
  • 2:1
  • 1:1
  • 1:2
  • 1:4
A rod of mass 'M' is subjected to force 't' and '2f' at both the ends as shown in the figure. If young modulus of its material is 'y' and its length is L find total elongation of rod.
1136358_9c97aad0427d4c3bbb0060bf21b9d8bd.png
  • \dfrac{fl}{2Ay}
  • \dfrac{fl}{Ay}
  • \dfrac{3fl}{2Ay}
  • \dfrac{4fl}{2Ay}
The bulk modulus of water is 2.1 \times 10^9 N/m^2. The pressure required to increase the density of water by 0.1% is:-
  • 2.1 \times 10^5 N/m^2
  • 2.1 \times 10^3 N/m^2
  • 2.1 \times 10^6 N/m^2
  • 2.1 \times 10^7 N/m^2
A wire is stretched by 0.01\ m by a certain force F. Another wire of same material whose diameter and lengths are doubled to the original wire is stretched by the same force. Then its elongation will be:
  • 0.005\ m
  • 0.01\ m
  • 0.02\ m
  • 0.08\ m
If the temperature of a wire of length 2m area of cross-section 1{cm}^2 is increased from {0^ \circ}C to {80^ \circ}C and is not allowed to increase in length, then force required for it is {Y = 10^{10}N/m^2, \alpha = 10^{ - 6}/^oC}
  • 80N
  • 160N
  • 400N
  • 120N
The pressure of a medium is changed from 1.01\times 10^{5}\ Pa to 1.165\times 10^{5}\ Pa and change in volume is 10\% keeping temperature constant. The bulk modulus of the medium is 
  • 204.8\times 10^{5}\ Pa
  • 102.4\times 10^{5}\ Pa
  • 51.2\times 10^{5}\ Pa
  • 1.55\times 10^{5}\ Pa
A copper wire is having length 2m and area of cross -section 2mm^2. Then amount of work done (in joule ) in increasing its length by 0.1mm will be (Young's modulus o elasticity for copper Y=1.2\times 10^{11}Nm^{-2} 
  • 6\times 10^4J
  • 6\times 10^{-3}J
  • 6\times 10^{3}J
  • 6\times 10^{-4}J
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Class 11 Engineering Physics Quiz Questions and Answers