RRB NTPC - Strength of Materials 1000+ MCQ [Solved] PDF Download

1. When wood is heated with a limited supply of air to a temperature not less than 280°C, the resulting fuel is
A. Coke
B. Wood charcoal
C. Bituminous coal
D. Briquetted coal
Answer : B

2. For the constant pressure and heat input, the air standard efficiency of gas power cycle is in the order
A. Dual cycle, Diesel cycle, Otto cycle
B. Otto cycle, Diesel cycle, Dual cycle
C. Dual cycle, Otto cycle, Diesel cycle
D. Diesel cycle, Otto cycle, Dual cycle
Answer : A

3. One kg of ethylene (C2H4) requires 2 kg of oxygen and produces 22/7 kg of carbon dioxide and __________ kg of water or steam.
A. 9/7
B. 11/7
C. 7/4
D. 1/4
Answer : A

4. The entropy may be expressed as a function of
A. Pressure and temperature
B. Temperature and volume
C. Heat and work
D. All of these
Answer : A

5. The efficiency of Ericsson cycle is __________ Carnot cycle.
A. Greater than
B. Less than
C. Equal to
D. None of these
Answer : C

6. Diesel cycle consists of __________ processes.
A. Two constant volume and two isentropic
B. Two constant pressure and two isentropic
C. Two constant volume and two isothermal
D. One constant pressure, one constant volume and two isentropic
Answer : D

7. According to Kelvin-Planck's statement, a perpetual motion of the __________ is impossible.
A. First kind
B. Second kind
C. Third kind
D. None of these
Answer : B

8. Which of the following statement is correct according to Clausis statement of second law of thermodynamics?
A. It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature.
B. It is impossible to transfer heat from a body at a lower temperature to a body at a higher temperature, without the aid of an external source.
C. It is possible to transfer heat from a body at a lower temperature to a body at a higher temperature by using refrigeration cycle.
D. None of the above
Answer : B

9. The capacity of a strained body for doing work on the removal of the straining force, is called
A. Strain energy
B. Resilience
C. Proof resilience
D. Impact energy
Answer : B

10. One reversible heat engine operates between 1600 K and T2 K and another reversible heat engine operates between T2 K and 400 K. If both the engines have the same heat input and output, then temperature T2 is equal to
A. 800 K
B. 1000 K
C. 1200 K
D. 1400 K
Answer : A

11. According to Avogadro's law, the density of any two gases is __________ their molecular masses, if the gases are at the same temperature and pressure.
A. Equal to
B. Directly proportional to
C. Inversely proportional to
D. None of these
Answer : B

12. Workdone in a free expansion process is
A. Zero
B. Minimum
C. Maximum
D. Positive
Answer : A

13. The neutral axis of the cross-section a beam is that axis at which the bending stress is
A. Zero
B. Minimum
C. Maximum
D. Infinity
Answer : A

14. The absolute zero temperature is taken as
A. -273°C
B. 73°C
C. 237°C
D. -237°C
Answer : A

15. A thin cylindrical shell of diameter (D) and thickness (t) is subjected to an internal pressure (p). The ratio of longitudinal strain to volumetric strain is
A. (m - 1)/ (2m - 1)
B. (2m - 1)/ (m - 1)
C. (m - 2)/ (3m - 4)
D. (m - 2)/ (5m - 4)
Answer : D

16. Otto cycle consists of
A. Two constant volume and two isentropic processes
B. Two constant pressure and two isentropic processes
C. Two constant volume and two isothermal processes
D. One constant pressure, one constant volume and two isentropic processes
Answer : A

17. Diamond riveted joint can be adopted in the case of following type of joint
A. Butt joint
B. Lap joint
C. Double riveted lap joints
D. All types of joints
Answer : A

18. Impact strength of a material is an index of its
A. Toughness
B. Tensile strength
C. Capability of being cold worked
D. Hardness
Answer : A

19. The fuel mostly used in steam boilers is
A. Brown coal
B. Peat
C. Coking bituminous coal
D. Non-coking bituminous coal
Answer : D

20. The temperature at which the volume of a gas becomes zero is called
A. Absolute scale of temperature
B. Absolute zero temperature
C. Absolute temperature
D. None of these
Answer : B

21. The work ratio of simple gas turbine cycle depends upon
A. Maximum cycle temperature
B. Minimum cycle temperature
C. Pressure ratio
D. All of these
Answer : D

22. Shear stress induced in a shaft subjected to tension will be
A. Maximum at periphery and zero at center
B. Maximum at center
C. Uniform throughout
D. None of the above
Answer : D

23. When it is indicated that a member is elastic, it means that when force is applied, it will
A. Not deform
B. Be safest
C. Stretch
D. Not stretch
Answer : C

24. Two closely coiled helical springs 'A' and 'B' are equal in all respects but the number of turns of spring 'A' is half that of spring 'B' The ratio of deflections in spring 'A' to spring 'B' is
A. 1/8
B. 1/4
C. 1/2
D. 2
Answer : C

25. One kg of carbon produces __________ kg of carbon dioxide.
A. 3/7
B. 7/3
C. 11/3
D. 3/11
Answer : C

26. The stress induced in a body, when suddenly loaded, is ________ the stress induced when the same load is applied gradually.
A. Equal to
B. One-half
C. Twice
D. Four times
Answer : C

27. Flow stress corresponds to
A. Fluids in motion
B. Breaking point
C. Plastic deformation of solids
D. Rupture stress
Answer : C

28. The safe twisting moment for a compound shaft is equal to the
A. Maximum calculated value
B. Minimum calculated value
C. Mean value
D. Extreme value
Answer : B

29. For same compression ratio and for same heat added
A. Otto cycle is more efficient than Diesel cycle
B. Diesel cycle is more efficient than Otto cycle
C. Efficiency depends on other factors
D. Both Otto and Diesel cycles are equally efficient
Answer : A

30. The stress developed in a material at breaking point in extension is called
A. Breaking stress
B. Fracture stress
C. Yield point stress
D. Ultimate tensile stress
Answer : A

31. The efficiency of Diesel cycle with decrease in cut-off
A. Increases
B. Decreases
C. First increases and then decreases
D. First decreases and then increases
Answer : A

32. A column of length (l) with both ends fixed may be considered as equivalent to a column of length __________ with both ends hinged.
A. l/8
B. l/4
C. l/2
D. l
Answer : C

33. A pressure vessel is said to be a thick shell, when
A. It is made of thick sheets
B. The internal pressure is very high
C. The ratio of wall thickness of the vessel to its diameter is less than 1/10.
D. The ratio of wall thickness of the vessel to its diameter is greater than 1/10.
Answer : D

34. Which of the following process can be made reversible with the help of a regenerator?
A. Constant pressure process
B. Constant volume process
C. Constant pvn process
D. All of these
Answer : D

35. Carnot cycle has maximum efficiency for
A. Petrol engine
B. Diesel engine
C. Reversible engine
D. Irreversible engine
Answer : C

36. The materials which exhibit the same elastic properties in all directions are called
A. Homogeneous
B. Inelastic
C. Isotropic
D. Isentropic
Answer : C

37. The efficiency of Carnot cycle is maximum for
A. Gas engine
B. Petrol engine
C. Steam engine
D. Reversible engine
Answer : D

38. For a beam, as shown in the below figure, the deflection at C is (where E = Young's modulus for the beam material, and I = Moment of inertia of the beam section.

A. Wl3/48 EI
B. Wa²b²/3EIl
C. [Wa/(a?3) x EIl] x (l² - a²)3/2
D. 5Wl3/384 EI
Answer : B

39. The hyperbolic process is governed by
A. Boyle's law
B. Charles' law
C. Gay-Lussac law
D. Avogadro's law
Answer : A

40. The efficiency of Stirling cycle is __________ Carnot cycle.
A. Greater than
B. Less than
C. Equal to
D. None of these
Answer : C

41. The stress necessary to initiate yielding is
A. Considerably greater than that necessary to continue it
B. Considerably lesser than that necessary to continue it
C. Greater than that necessary to stop it
D. Lesser than that necessary to stop it
Answer : A

42. The tensile strength of the welded joint for double fillet is (where s = Leg or size of the weld, l = Length of weld, and ?t = Allowable tensile stress for weld metal)
A. 0.5 s.l.?_t
B. s.l.?_t
C. ?2 s.l.?_t
D. 2.s.l.?t
Answer : C

43. When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel, the process is known as __________ of fuel.
A. Atomisation
B. Carbonisation
C. Combustion
D. None of these
Answer : B

44. In the below figure, curve D represents_________.

A. Mild steel
B. Cast iron
C. Concrete
D. Bone of these
Answer : A

45. The efficiency of Diesel cycle increases with
A. Decrease in cut-off
B. Increase in cut-off
C. Constant cut-off
D. None of these
Answer : A

46. The amount of heat generated per kg of fuel is known as
A. Calorific value
B. Heat energy
C. Lower calorific value
D. Higher calorific value
Answer : A

47. Mond gas is obtained by
A. Partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast
B. Carbonisation of bituminous coal
C. Passing steam over incandescent coke
D. Passing air and a large amount of steam over waste coal at about 650°C
Answer : D

48. The intensity of stress which causes unit strain is called
A. Unit mass
B. Modulus of rigidity
C. Bulk modulus
D. Modulus of Elasticity
Answer : D

49. The stress at which extension of the material takes place more quickly as compared to the increase in load is called
A. Elastic point of the material
B. Plastic point of the material
C. Breaking point of the material
D. Yielding point of the material
Answer : D

50. The compression ratio for petrol engines is
A. 3 to 6
B. 5 to 8
C. 15 to 20
D. 20 to 30
Answer : B