LIC AAO - Engineering Materials 1000+ MCQ [Solved] PDF Download

1. Hardness of lower bainite (tempered martensite) is about
A. RC 65
B. RC 48
C. RC 57
D. RC 80
Answer : C

2. Quenching is not necessary when hardening is done by
A. Case hardening
B. Flame hardening
C. Nitriding
D. Any one of these
Answer : C

3. Grey cast iron
A. Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
B. Is also known as chilled cast iron is obtained by cooling rapidly. It is almost unmachinable
C. Is produced by annealing process. I is soft, tough and easily machined metal
D. Is produced by small additions o magnesium (or cerium) in the ladle Graphite is in nodular or spheroidal form and is well dispersed throughout the material
Answer : A

4. Which of the following material has maximum ductility?
A. Mild steel
B. Copper
C. Nickel
D. Aluminium
Answer : A

5. In basic Bessemer process, the furnace is lined with
A. Silica bricks
B. A mixture of tar and burnt dolomite bricks
C. Both (A) and (B)
D. None of these
Answer : B

6. Cast iron is a
A. Ductile material
B. Malleable material
C. Brittle material
D. Tough material
Answer : C

7. The hardness of steel increases if it contains
A. Austenite
B. Martensite
C. Pearlite
D. Cementite
Answer : B

8. Hardness of steel depends on
A. Amount of carbon it contains
B. The shape and distribution of the carbides in iron
C. Method of fabrication
D. Contents of alloying elements
Answer : B

9. The percentage of carbon in low carbon steel is
A. 0.05 %
B. 0.15 %
C. 0.3 %
D. 0.5 %
Answer : B

10. Free carbon in iron makes the metal
A. Soft and gives a coarse grained crystalline structure
B. Soft and gives a fine grained crystalline structure
C. Hard and gives a coarse grained crystalline structure
D. Hard and gives a fine grained crystalline structure
Answer : A

11. The correct composition of Babbitt metal is
A. 87.75% Sn, 4% Cu, 8% Sb, 0.25% Bi
B. 90% Sn, 2% Cu, 4% Sb, 2% Bi, 2% Mg
C. 87% Sn, 4% Cu, 8% Sb, 1% Al
D. 82% Sn, 4% Cu, 8% Sb, 3% Al, 3% Mg
Answer : A

12. Which of the following statement is incorrect about duralumin?
A. It is prone to age hardening
B. It can be forged
C. It has good machining properties
D. It is lighter than pure aluminium
Answer : D

13. The maximum internal diameter of a blast furnace is about
A. 3 m
B. 6 m
C. 9 m
D. 12 m
Answer : C

14. Steel contains
A. 80% or more iron
B. 50% or more iron
C. Alloying elements like chromium, tungsten nickel and copper
D. Elements like phosphorus, sulphur and silicon in varying quantities
Answer : B

15. Pick up the wrong statement
A. Aluminium in steel results in excessive grain growth
B. Manganese in steel induces hardness
C. Nickel and chromium in steel helps in raising the elastic limit and improve the resilience and ductility
D. Tungsten in steels improves magnetic properties and hardenability
Answer : A

16. Which is false statement about case hardening? Case hardening is done by
A. Electroplating
B. Cyaniding
C. Induction hardening
D. Nitriding
Answer : A

17. High carbon steel carries carbon percentage
A. 0.1 to 0.3 %
B. 0.3 to 0.6 %
C. 0.6 to 0.8 %
D. 0.8 to 1.5 %
Answer : D

18. There are fourteen atoms in a unit cell of
A. Body centred cubic space lattice
B. Face centred cubic space lattice
C. Close packed hexagonal space lattice
D. None of these
Answer : B

19. Process of Austempering results in
A. Formation of bainite structure
B. Carburised structure
C. Martenistic structure
D. Lamellar layers of carbide distributed throughout the structure
Answer : A

20. Which of the following statements are true for annealing of steels?
A. Steels are heated to 500 to 700°C
B. Cooling is done slowly and steadily
C. Internal stresses are relieved
D. All of these
Answer : D

21. Neutral solution is one which has pH value
A. Greater than 7
B. Less than 7
C. Equal to 7
D. pH value has nothing to do with neutral solution
Answer : C

22. Brass (alloy of copper and zinc) is an example of
A. Substitutional solid solution
B. Interstitial solid solution
C. Intermetallic compounds
D. All of the above
Answer : A

23. Eutectoid steel contains following percentage of carbon
A. 0.02 %
B. 0.3 %
C. 0.63 %
D. 0.8 %
Answer : D

24. Dislocations in materials refer to the following type of defect
A. Point defect
B. Line defect
C. Plane defect
D. Volumetric defect
Answer : B

25. Dye penetrant method is generally used to locate
A. Core defects
B. Surface defects
C. Superficial defects
D. Temporary defects
Answer : B

26. The ability of a material to absorb energy in the plastic range is called
A. Resilience
B. Creep
C. Fatigue strength
D. Toughness
Answer : A

27. Steel with ________ carbon is known as hypo-eutectoid steel.
A. 0.8 %
B. Below 0.8 %
C. Above 0.8 %
D. None of these
Answer : B

28. Drop forging dies contain carbon of the order of
A. 0.1 to 0.2 %
B. 0.25 to 0.5 %
C. 0.6 to 0.7 %
D. 0.7 to 0.9 %
Answer : C

29. The molecules in a solid move
A. In a random manner
B. In a haphazard way
C. In circular motion
D. Back and forth like tiny pendulums
Answer : D

30. For a steel containing 0.8% carbon
A. There is no critical point
B. There is only one critical point
C. There are two critical points
D. There can be any number of critical points
Answer : B

31. Lead is poured into the joint between two pipes. These pipes may be made of
A. Cast iron
B. Vitrified clay
C. Asbestos cement
D. Concrete
Answer : A

32. Constantan an alloy used in thermocouples is an alloy of
A. Copper and tin
B. Copper and zinc
C. Copper and iron
D. Copper and nickel
Answer : D

33. Slow plastic deformation of metals under a constant stress is known as
A. Creep
B. Fatigue
C. Endurance
D. Plastic deformation
Answer : A

34. Which of the following represents the allotropic forms of iron?
A. Alpha iron, beta iron and gamma iron
B. Alpha iron and beta iron
C. Body centred cubic iron and face centred cubic iron
D. Alpha iron, gamma from and delta iron
Answer : D

35. The unique property of cast iron is its high
A. Malleability
B. Ductility
C. Surface finish
D. Damping characteristics
Answer : D

36. Corrosion resistance of steel is increased by addition of
A. Chromium and nickel
B. Sulphur, phosphorus, lead
C. Vanadium, aluminium
D. Tungsten, molybdenum, vanadium, chromium
Answer : A

37. Which of the following impurity in cast iron makes it hard and brittle?
A. Silicon
B. Sulphur
C. Manganese
D. Phosphorus
Answer : B

38. The toughness of a material __________ when it is heated.
A. Remain same
B. Decreases
C. Increases
D. None of these
Answer : B

39. Manganese is added in low carbon steel to
A. Make the steel tougher and harder
B. Raise the yield point
C. Make the steel ductile and of good bending qualities
D. All of the above
Answer : C

40. Y-alloy contains
A. 3.5 to 4.5% copper, 0.4 to 0.7% magnesium, 0.4 to 0.7% manganese and rest aluminium
B. 3.5 to 4.5% copper, 1.2 to 1.7% manganese, 1.8 to 2.3% nickel, 0.6% each of silicon, magnesium and iron, and rest aluminium
C. 4 to 4.5% magnesium, 3 to 4% copper and rest aluminium
D. 5 to 6% tin, 2 to 3% copper and rest aluminium
Answer : B

41. Preheating is essential in welding
A. Cast iron
B. High speed steel
C. All nonferrous materials
D. All of the above
Answer : A

42. In grey cast iron, carbon is present in the form of
A. Cementite
B. Free carbon
C. Flakes
D. Spheroids
Answer : C

43. The material in which the atoms are arranged chaotically, is called
A. Amorphous material
B. Mesomorphous material
C. Crystalline material
D. None of these
Answer : A

44. The property of a material essential for spring materials is
A. Stiffness
B. Ductility
C. Resilience
D. Plasticity
Answer : C

45. Aluminium bronze contains
A. 94% aluminium, 4% copper and 0.5% Mn, Mg, Si and Fe
B. 92.5% aluminium, 4% copper, 2% nickel, and 1.5% Mg
C. 10% aluminium and 90% copper
D. 90% magnesium and 9% aluminium with some copper
Answer : C

46. Perminvar alloy having constant permeability is an alloy of
A. Nickel, copper and iron
B. Nickel, copper and zinc
C. Copper, nickel and antimony
D. Iron, zinc and bismuth
Answer : A

47. Which is false statement about tempering? Tempering is done to
A. Improve machinability
B. Improve ductility
C. Improve toughness
D. Release stresses
Answer : A

48. Malleable cast iron is produced
A. By adding magnesium to molten cast iron
B. By quick cooling of molten cast iron
C. From white cast iron by annealing process
D. None of these
Answer : C

49. Austenite is a combination of
A. Ferrite and cementite
B. Cementite and gamma iron
C. Ferrite and austenite
D. Ferrite and iron graphite
Answer : B

50. The bond formed by transferring electrons from one atom to another is called
A. Ionic bond
B. Covalent bond
C. Metallic bond
D. None of these
Answer : A