Wednesday, 1 October 2014

ELASTICITY MULTIPLE CHOICE QUESTIONS

1. When a certain weight is suspended from a long uniform wire, its length increases by one cm. If the same weight is suspended from another wire of the same material and length but having a diameter half of the first one then the increase in length will be . [CPMT 1984, 90]
 0.5 cm 4 cm 2 cm 8 cm

2. The bulk modulus of an ideal gas at constant temperature . [MP PMT 2004]
 Is equal to its volume V Is equal to its pressure p Is equal to p/2 Can not be determined

3. The longitudinal strain is only possible in
 Gases Solids Fluids Liquids

4. The area of cross-section of a wire of length 1.1 metre is 1 mm2. It is loaded with 1 kg. If Young's modulus of copper is 1.1 * 1011 N/m2 , then the increase in length will be (If g = 10). [MP PET 1989]
 0.01 mm 0.1 mm 0.075 mm 0. 15 mm

5. If Young's modulus of iron is 2*1011 N/m2 and the interatomic spacing between two molecules is 3*10-10metre, the interatomic force constant is . [JIPMER 1978]
 60 N/m 30 N/m 120 N/m 180 N/m

6. The isothermal elasticity of a gas is equal to . [CPMT 1981; MP P]
 Density Pressure Volume Specific heat

7. A steel wire is stretched with a definite load. If the Young's modulus of the wire is Y. For decreasing the value of Y
 Radius is to be decreased Length is to be increased Radius is to be increased None of the above

8. The force constant of a wire does not depend on
 Nature of the material Length of the wire Radius of the wire None of the above

9. The elasticity of invar
 Increases with temperature rise Does not depend on temperature Decreases with temperature rise None of the above

10. The ratio of the lengths of two wires A and B of same material is 1 : 2 and the ratio of their diameter is 2 : 1. They are stretched by the same force, then the ratio of increase in length will be. [MP PET/PMT 1988]
 2 : 1 1 : 8 1 : 4 8 : 1

11. Which statement is true for a metal. [DPMT 2001]
 Y < η Y > η Y = η Y < 1/η

12. The Young's modulus of a wire of length L and radius r is Y N/m2. If the length and radius are reduced to L/2 and r/2, then its Young's modulus will be . [MP PET 1997; KC]
 Y/2 2Y Y 4Y

13. If the temperature increases, the modulus of elasticity
 Decreases Remains constant Increases Becomes zero

14. After effects of elasticity are maximum for
 Glass Rubber Quartz Metal

15. The ratio of lengths of two rods A and B of same material is 1 : 2 and the ratio of their radii is 2 : 1, then the ratio of modulus of rigidity of A and B will be
 4 : 1 8 : 1 16 : 1 1 : 1
16. Hook's law defines . [MP PMT/PET 1988]
 Stress Modulus of elasticity Strain Elastic limit

17. In a wire of length L, the increase in its length is l. If the length is reduced to half, the increase in its length will be
 l l/2 2l None of the above

18. Modulus of rigidity of diamond is
 Too less Less than all matters Greater than all matters Zero

19. The extension of a wire by the application of load is 3 mm. The extension in a wire of the same material and length but half the radius by the same load is . [CMEET Bihar 199]
 12 mm 15 mm 0.75 mm 6 mm

20. Density of rubber is d. A thick rubber cord of length L and cross-section area A undergoes elongation under its own weight on suspending it. This elongation is proportional to
21. The compressibility of a material is
 Product of volume and its pressure The fractional change in volume per unit change in pressure The change in pressure per unit change in volume strain None of the above

22. If Young's modulus for a material is zero, then the state of material should be
 Solid Gas Solid but powder None of the above

23. The quality of the material which opposes the change in shape, volume or length is called
 Intermolecular repulsion Viscosity Intermolecular behaviour Elasticity

24. A wire extends by 1 mm when a force is applied. Double the force is applied to another wire of same material and length but half the radius of cross-section. The elongation of the wire in mm will be. [EAMCET 1986]
 8 2 4 1

25. If the length of a wire is reduced to half, then it can hold the ......... load
 Half Double Same One fourth

26. The ratio of the adiabatic to isothermal elasticities of a triatomic gas is. [MP PET 1991]
 3/4 1 4/3 5/3

27. The possible value of Poisson's ratio is . [EAMCET (Med.) 1]
 1 0.8 0.9 0.4

28. The dimensions of four wires of the same material are given below. In which wire the increase in length will be maximum when the same tension is applied . [IIT 1981;CPMT 1]
 Length 100 cm, Diameter 1 mm Length 300 cm, Diameter 3 mm Length 200 cm, Diameter 2 mm Length 50 cm, Diameter 0.5 mm

29. The increase in length is l of a wire of length L by the longitudinal stress. Then the stress is proportional to .[MP PET 1986]
 L/l l*L l/L l2*L

30. Two wires of equal lengths are made of the same material. Wire A has a diameter that is twice as that of wire B. If identical weights are suspended from the ends of these wires, the increase in length is . [MP PMT 1990; MP]
 Four times for wire A as for wire B Half for wire A as for wire B Twice for wire A as for wire B One-fourth for wire A as for wire B
31. A and B are two wires. The radius of A is twice that of B. They are stretched by the some load. Then the stress on B is . [MP PMT 1993]
 Equal to that on A Two times that on A Four times that on A Half that on A

32. Which one of the following quantities does not have the unit of force per unit area. [MP PMT 1992]
 Stress Young's modulus of elasticity Strain Pressure

33. When compared with solids and liquids, the gases have
 Minimum volume elasticity Maximum Young's modulus Maximum volume elasticity Maximum modulus of rigidity

34. A copper wire and a steel wire of the same diameter and length are connected end to end and a force is applied, which stretches their combined length by 1 cm. The two wires will have. [MP PMT 1992]
 Different stresses and strains The same strain but different stresses The same stress and strain The same stress but different strains

35. Two identical wires of rubber and iron are stretched by the same weight, then the number of atoms in the iron wire will be . [DPMT 1999]
 Equal to that of rubber More than that of the rubber Less than that of the rubber None of the above

36. When a spiral spring is stretched by suspending a load on it, the strain produced is called
 Shearing Volume Longitudinal Transverse

37. The material which practically does not show elastic after effect is. [JIPMER 1997; AM]
 Copper Steel Rubber Quartz

38. The spring balance does not read properly after its long use, because
 The elasticity of spring increases Its plastic power decreases The elasticity decreases Its plastic power increases

39. Two wires of copper having the length in the ratio 4 : 1 and their radii ratio as 1 : 4 are stretched by the same force. The ratio of longitudinal strain in the two will be
 1 : 16 1 : 64 16 : 1 64 : 1

40. In the three states of matter, the elastic coefficient can be
 Young's modulus Modulus of rigidity Coefficient of volume elasticity Poisson's ratio

41. A rod of length l and area of cross-section A is heated from 0°C to 100°C. The rod is so placed that it is not allowed to increase in length, then the force developed is proportional to . [NCERT 1976]
 l A l-1 A-1

42. A force F is needed to break a copper wire having radius R. The force needed to break a copper wire of radius 2R will be . [MP PET 1990]
 F/2 4F 2F F/4

43. Modulus of rigidity of a liquid. [RPET 2000]
 Non zero constant Zero Infinite Can not be predicted

44. If the density of the material increases, the value of Young's modulus
 Increases First increases then decreases Decreases First decreases then increases

45. Increase in length of a wire is 1 mm when suspended by a weight. If the same weight is suspended on a wire of double its length and double its radius, the increase in length will be . [CPMT 1976]
 2 mm 4 mm . 0.5 mm 0.25 mm