Class 11 Physics — Chapter 9: Mechanical Properties of Solids Online Test

1. A material initially stressed to shows a stress of after 100 s at constant strain. What is the relaxation time ?

2. A boiler tube operates under stress of at . If the creep rate follows Norton’s law , what happens if stress doubles?

3. In an S–N curve (stress vs. number of cycles), what does the horizontal region represent?

4. In which of the following processes is strain hardening most beneficial?

5. Plastic deformation is accompanied by which atomic process?

6. For submarine hull design, which modulus is most relevant?

7. A material has Young’s modulus and bulk modulus . Find Poisson’s ratio .

8. A wire of length , area , elongates by under a load of . Find Young’s modulus.

9. A wire of length and area is stretched with stress of . If , calculate elongation.

10. What type of deformation occurs in the yield region?

11. Which industrial test uses Hooke’s law principle to check stiffness of materials?

12. A copper wire of length and cross-sectional area is subjected to a tensile force of . If , what is the elongation?

13. Which graph best represents the equation ?

14. The stress–strain graph in Hooke’s law region is:

15. A wire of length and cross-sectional area elongates by under a force of . What is the stress and strain?

16. Plasticity in solids refers to:

17. Which property is most important for designing wires used in electrical transmission?

18. Which of the following is an example of a linear elastic material?

19. A wire of length and area is subjected to a tensile force of . If its elongation is , what is the Young’s modulus of the material?

20. A steel wire of length and radius is subjected to a tensile force of . If Young’s modulus of steel is , what is the elongation of the wire?

1. Which modulus determines how a liquid resists compression?

2. A steel rod of length and cross-sectional area is subjected to a tensile force of . If elongation is , find Young’s modulus.

3. Which property of alloys is most critical for preventing creep in jet engines?

4. Why is elasticity important in the design of artificial heart valves?

5. Which property is most critical in designing railway tracks?

6. Which of the following pairs correctly matches ductile and brittle material behaviour?

7. What does a higher value of Young’s modulus imply about a material?

8. What does the stress–strain relationship describe?

9. Which property makes rubber suitable for making shock absorbers?

10. Why is elasticity an important property in making sports shoes?

11. Which point on the stress–strain curve marks the end of elastic behaviour?

12. Hooke’s law fails when:

13. Bulk modulus can be measured experimentally by studying:

14. Which process of manufacturing depends directly on plastic deformation of metals?

15. Which of the following quantities can be calculated in materials testing using Hooke’s law?

16. Which part of the stress–strain curve corresponds to permanent deformation?

17. Which modulus is relevant in calculating the speed of sound in a liquid?

18. In Searle’s experiment, why are two wires used (test wire and reference wire)?

19. Why is stress relaxation test significant for materials used in gaskets and seals?

20. The proportionality limit corresponds to which part of the stress–strain curve?

21. Which modulus is most relevant in studying deformation of blood vessels under blood pressure?

22. A rod is subjected to uniform stress of . If volume = , Young’s modulus = , find strain energy stored.

23. Which modulus is most relevant for describing elasticity in solids under torsion?

24. A copper wire is stretched beyond its elastic limit. What type of deformation occurs?

25. Why is measurement of elastic moduli important in engineering?

26. What is strain hardening?

27. What is shear modulus (also called modulus of rigidity) defined as?

28. Which of the following properties decreases due to cold working?

29. If two wires of same material, same length, but different cross-sectional areas are subjected to same force, then:

30. A steel rod of length and area is subjected to a tensile force of . Calculate strain energy stored.

1. Which property ensures that metallic wires can be drawn into fine wires during wire-drawing?

2. Which of the following examples follows Hooke’s law most closely?

3. Which process of manufacturing depends directly on plastic deformation of metals?

4. Which property decreases after annealing compared to strain hardening?

5. In a tensile test, why is stress–strain curve plotted?

6. A rod is subjected to uniform stress of . Volume = . . Find strain energy stored.

7. Why does ductility decrease during strain hardening?

8. Why is it important to test materials under Hooke’s law conditions before use in construction?

9. Which parameter is commonly used to describe fatigue strength of a material?

10. Which physical quantity is defined as force per unit area?

11. What does the stress–strain relationship describe?

12. Shear stress is defined as:

13. Which characteristic feature is observed in brittle material’s stress–strain curve?

14. Which statement about plastic deformation is correct?

15. Why is proportionality limit lower than elastic limit?

16. In material science, why is Young’s modulus important for engineers?

17. Why are elastic properties of polymers studied in manufacturing packaging materials?

18. Which characteristic differentiates plastic flow from creep?

19. Why is elasticity an important property in making sports shoes?

20. In the elastic region, the relation between stress () and strain () is given by:

21. Which of the following statements is correct about strain hardening?

22. What does brittleness of a material mean?

23. A rod of length , cross-sectional area , is compressed longitudinally by . If Young’s modulus , find applied force.

24. Why is stress relaxation important in designing bolts and fasteners?

25. If stress is below proportionality limit, then:

26. At which point on the stress–strain curve does the material bear the maximum stress?

27. A steel wire of radius , length , is twisted through angle . If torque required = , calculate shear modulus.

28. Which of the following always lies before the elastic limit on a stress–strain curve?

29. Bulk modulus can be measured experimentally by studying:

30. If creep rate is given by , and activation energy increases, what happens to creep rate?

31. When does a body show perfectly elastic behavior?

32. Why is studying plastic deformation important in material science?

33. In the equation , what does represent?

34. Which relation connects Young’s modulus , shear modulus , and Poisson’s ratio ?

35. Which of the following techniques increases creep resistance of metals?

36. A wire of length and area is subjected to a tensile force of . If its elongation is , what is the Young’s modulus of the material?

37. A liquid has bulk modulus . If pressure of is applied, what is the fractional volume change?

38. Why is creep prevention essential in nuclear reactors?

39. Which modulus is most relevant for describing elasticity in solids under torsion?

40. Which modulus determines how a liquid resists compression?

41. A cylindrical rod of radius , length , is subjected to shear stress of . If shear modulus , find the lateral displacement of top face.

42. What is the dimensional formula of Young’s modulus ?

43. What does Hooke’s law state?

44. In which type of materials is stress relaxation most significant at room temperature?

45. Which property makes elastic catheters effective in medical applications?

46. Which of the following is the most important factor affecting creep rate in metals?

47. Which graph best represents the equation ?

48. Why is cold working directly associated with strain hardening?

49. Which equation represents stress relaxation behavior in viscoelastic materials (Maxwell model)?

50. Which of the following laboratory devices is commonly used to test Hooke’s law in wires?