Mechanical Properties of Solids Mock Test – Class 11 Physics

1. The unit of compressibility is

2. A cable must carry a load of . Its length is , , breaking stress is , and the factor of safety is . If its extension must not exceed , the minimum cross-sectional area required is

3. The force-extension graph of a wire is a straight line through the origin. If the graph becomes twice as steep after replacing the wire, then for the same final load the extension becomes

4. A wire under a tensile load is analysed using the original area , even though the wire becomes slightly thinner while stretching. This is acceptable in the elementary formula mainly because

5. The dimensional formula of compressibility is

6. A cable of area carries a load of . Its breaking stress is . The factor of safety is

7. A cable design must satisfy both strength and extension limits. Which pair of checks is most appropriate?

8. A metal specimen is stretched beyond the proportionality limit but is unloaded before the elastic limit is crossed. The most suitable observation is that it

9. A wire is stretched to a longitudinal strain of . Its Poisson’s ratio is . Using the small-strain estimate , the approximate volume strain is

10. A solid block of height and top-face area is sheared by a tangential force . If the material has shear modulus , the sideways displacement of the top face is

11. Consider the following statements about bulk modulus.
I. It relates pressure change to volumetric strain.
II. Its SI unit is .
III. A larger value usually means the material is less compressible.
IV. It is dimensionless because volumetric strain is dimensionless.
The suitable set is

12. A metal wire is stretched within the elastic limit. Its load-extension graph is a straight line through the origin with load on the vertical axis and extension on the horizontal axis. The slope of this graph is

13. In a material test, the following observations are made: the first part of the stress-strain graph is straight; after that the curve bends; still later, unloading leaves permanent strain. The sequence of ideas represented is

14. A wire of length , area , and is stretched by a load of . The elastic energy stored is

15. A stretched metal wire becomes slightly thinner while its length increases. With the usual sign convention, the longitudinal strain and lateral strain are respectively

16. For a solid compressed uniformly by an increase in pressure , the bulk modulus is commonly written as . The negative sign is used because

17. A wire of length and radius is stretched by a gradually applied load. Its breaking stress is , , and it is used at factor of safety . Taking , the elastic energy stored at the safe working load is closest to

18. Two rods have the same cross-sectional area. Rod carries a tensile force , while rod carries a tensile force . The tensile stress in rod is

19. The load-extension graph of a wire is straight only up to a certain load. Data taken after the graph bends should not be used in as though the slope were constant because

20. Consider the statements about shear deformation.
I. Shearing stress is produced by tangential force per unit area.
II. Shearing strain can be written as for small deformation.
III. Shear modulus has unit .
IV. Shear modulus measures resistance to volume change under uniform pressure.
The suitable set is

21. A load-extension graph for a wire is a straight line with slope . The wire has length and cross-sectional area . Young’s modulus of the wire material is

22. Two wires of equal length are fixed side by side between the same two supports and carry a total load of . Wire has , , while wire has , . The load carried by , load carried by , and common extension are

23. An isotropic material has and . Using , and then , the values of and are closest to

24. Assertion : A perfectly elastic body regains its original shape and size after the deforming force is removed.
Reason : Elastic recovery is connected with the restoring force developed inside the body during deformation.

25. A tensile test record says that the maximum load occurs before the specimen finally breaks, and after that point the recorded load decreases while elongation continues. The best graph interpretation is that

26. A stress-strain curve of a metal is described as follows: the initial part is straight, unloading from a later curved part still gives full recovery, unloading from a still later part leaves a permanent set, and the highest point of stress occurs before final fracture. The correct interpretation is

27. In the expression for stress, the force is divided by the area over which it acts. The area used in is important because

28. A wire is stretched in the linear elastic range. Its stress is increased from to , while the material remains the same. The elastic energy density becomes

29. Assertion : A rubber band can return nearly to its original length after unloading even when its stress-strain curve is non-linear.
Reason : Elastic recovery and exact proportionality between stress and strain are the same condition.

30. A safe structural member must carry a tensile load without breaking and must also not stretch more than a specified limit. The two checks should use

31. A stress-strain graph for a wire is a straight line from the origin up to the working point. The area under the graph up to that point represents

32. Use the testing notes below.

The correct matching is

33. A table gives observations from three different materials tested under suitable elastic conditions.

The correct matching is

34. A wire of radius is stretched by a load of . The tensile stress in the wire is closest to

35. A solid block is sheared so that the shearing stress is and the shearing strain is . Its shear modulus is

36. For many ordinary comparisons, gases are more compressible than liquids and solids. In terms of bulk modulus, this means gases usually have

37. A table compares three materials under the same pressure increase.

The material with largest bulk modulus and the material with largest shear modulus are respectively

38. A wire of radius , length , and Young’s modulus is stretched by a force . A second wire of the same material is stretched by force , has length , and must have the same extension as the first wire. Its radius should be

39. A wire of original diameter is stretched to a longitudinal strain of . If , the decrease in diameter is

40. When a spring is stretched slightly and held at rest, an internal force develops in the spring. This internal force mainly acts to

41. A material has and . If it is isotropic and obeys , Poisson’s ratio is

42. A wire of radius , length , and Young’s modulus is stretched by force . A second wire of the same material is to have the same extension under the same force but has length . Its radius should be

43. A square concrete pillar of side supports a load of . The average compressive stress in the pillar is

44. A rod of Young’s modulus and coefficient of linear expansion is heated by , but its expansion is completely prevented. If the formula is supplied, the thermal stress depends on

45. A wire is stretched by a load, and its extension is measured. The calculation of Young’s modulus from requires the original length , not the final length, because

46. A wire is stretched within the elastic limit. The elastic energy density is , and the volume of the stretched part is . The total elastic energy stored is

47. In a tensile test, a wire reaches a maximum stress of and finally fractures at a stress of . The value represents

48. A wire used in is assumed to be uniform. If the wire is actually thinner at one section, the main reason the simple calculation can become unreliable is that

49. A block is sheared so that the sideways displacement of the top face is not small compared with the block height. The relation becomes questionable mainly because

50. A load-extension graph for a wire is linear. At a certain point, and . The wire has and . The corresponding stress, strain, and elastic energy density are