1000+ Strength of Materials Multiple Choice Question Answer [Solved]

1. A material obeys hooks law up to
A. Plastic limit
B. Elastic limit
C. Yield point
D. Limit of proportionality
Answer : B

2. The energy stored in a body when strained within elastic limit is known as
A. Resilience
B. Proof resilience
C. Strain energy
D. Impact energy
Answer : C

3. A definite area or a space where some thermodynamic process takes place is known as
A. Thermodynamic system
B. Thermodynamic cycle
C. Thermodynamic process
D. Thermodynamic law
Answer : A

4. Which is the incorrect statement about Carnot cycle?
A. It is used as the alternate standard of comparison of all heat engines.
B. All the heat engines are based on Carnot cycle.
C. It provides concept of maximising work output between the two temperature limits.
D. All of the above
Answer : B

5. 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

6. Carbonisation of coal consists of
A. Drying and crushing the coal to a fine powder
B. Moulding the finely ground coal under pressure with or without a binding material
C. Heating the wood with a limited supply of air to temperature not less than 280°C
D. None of the above
Answer : D

7. In order to prevent crushing of masonry at the base of the dam, the maximum stress should be __________ the permissible stress of the soil.
A. Equal to
B. Less than
C. More than
D. None of these
Answer : B

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

9. The efficiency of a gas turbine is given by
A. (Net work output)/(Workdone by the turbine)
B. (Net work output)/(Heat supplied)
C. (Actual temperature drop)/(Isentropic temperature drop)
D. (Isentropic increase in temperature)/(Actual increase in temperature)
Answer : B

10. The compression ratio for petrol engines is
A. 3 to 6
B. 5 to 8
C. 10 to 20
D. 15 to 30
Answer : B

11. In a reversible adiabatic process, the ratio of T1/T2 is equal to
A. (p₂/p₁)? - 1/ ?
B. (p₁/p₂)? - 1/ ?
C. (v₂/v₁)? - 1/ ?
D. (v₁/v₂)? - 1/ ?
Answer : B

12. When a body is subjected to a direct tensile stress (?) in one plane, then maximum normal stress occurs at a section inclined at __________ to the normal of the section.
A. 0°
B. 30°
C. 45°
D. 90°
Answer : A

13. In the tensile test, the phenomenon of slow extension of the material, i. e. stress increasing with the time at a constant load is called
A. Creeping
B. Yielding
C. Breaking
D. Plasticity
Answer : A

14. 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

15. The condition for the reversibility of a cycle is
A. The pressure and temperature of the working substance must not differ, appreciably, from those of the surroundings at any stage in the process
B. All the processes, taking place in the cycle of operation, must be extremely slow
C. The working parts of the engine must be friction free
D. All of the above
Answer : D

16. 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

17. The efficiency of the Carnot cycle is (where T1 and T2 = Highest and lowest temperature during the cycle)
A. (T₁/T₂) - 1
B. 1 - (T₁/T₂)
C. 1 - (T₂/T₁)
D. 1 + (T₂/T₁)
Answer : C

18. 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

19. During which of the following process does heat rejection takes place in Carnot cycle?
A. Isothermal expansion
B. Isentropic expansion
C. Isothermal compression
D. Isentropic compression
Answer : C

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

21. The ratio of maximum shear stress developed in a rectangular beam and a circular beam of the same cross-sectinal area is
A. 2/3
B. 3/4
C. 1
D. 9/8
Answer : D

22. A bar of copper and steel form a composite system, which is heated to a temperature of 40°C. The stress induced in the copper bar will be
A. Tensile
B. Compressive
C. Shear
D. Zero
Answer : B

23. For the same compression ratio, the efficiency of dual combustion cycle is
A. Greater than Diesel cycle and less than Otto cycle
B. Less than Diesel cycle and greater than Otto cycle
C. Greater than Diesel cycle
D. Less than Diesel cycle
Answer : A

24. A cube subjected to three mutually perpendicular stress of equal intensity p expenses a volumetric strain
A. 3p/E × (2/m - 1)
B. 3p/E × (2 - m)
C. 3p/E × (1 - 2/m)
D. E/3p × (2/m - 1)
Answer : C

25. The ultimate tensile stress of mild steel compared to ultimate compressive stress is
A. Same
B. More
C. Less
D. Unpredictable
Answer : B

26. The general law of expansion or compression is pvn = C, The process is said to be hyperbolic, if n is equal to
A. 0
B. 1
C. ?
D. ?
Answer : B

27. Modulus of rigidity is defined as the ratio of
A. Longitudinal stress to longitudinal strain
B. Volumetric stress to volumetric strain
C. Lateral stress to Lateral strain
D. Shear stress to shear strain
Answer : D

28. The efficiency and work ratio of a simple gas turbine cycle are
A. Very low
B. Low
C. High
D. Very high
Answer : A

29. The increase in entropy of a system represents
A. Increase in availability of energy
B. Increase in temperature
C. Decrease in pressure
D. Degradation of energy
Answer : D

30. The calorific value of gaseous fuel is expressed in
A. kJ
B. kJ/kg
C. kJ/m²
D. kJ/m³
Answer : D

31. The radius of the Mohrs circle in the given figure is equal to

A. Sum of two principal stresses
B. Difference of two principal stresses
C. Half the sum of two principal stresses
D. Half the difference of two principal stresses
Answer : D

32. If a material expands freely due to heating it will develop
A. Thermal stresses
B. Tensile stress
C. Bending
D. No stress
Answer : D

33. 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

34. In a uniform bar, supported at one end in position, the maximum stress under self weight of bar shall occur at the
A. Middle of bar
B. Supported end
C. Bottom end
D. None of these
Answer : B

35. Select the wrong statement
A. A Joule cycle consists of two constant volume and two isentropic processes.
B. An Otto cycle consists of two constant volume and two isentropic processes.
C. An Ericsson cycle consists of two constant pressure and two isothermal processes.
D. All of the above
Answer : A

36. The entropy of water at 0°C is assumed to be
A. 1
B. 0
C. -1
D. 10
Answer : B

37. Volumetric strain for a rectangular specimen of length l, breadth b and thickness t subjected to a pull of P is given by
A. e (1 - 2m)
B. e (1 - 2/m)
C. e (m - 2)
D. e (2/m - 1)
Answer : B

38. When a bar is subjected to a change of temperature and its deformation is prevented, the stress induced in the bar is
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Thermal stress
Answer : D

39. When cut-off ratio is __________ the efficiency of Diesel cycle approaches to Otto cycle efficiency.
A. Zero
B. 1/5
C. 4/5
D. 1
Answer : A

40. 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

41. In open cycle gas turbine plants
A. The indirect heat exchanger and cooler is avoided
B. Direct combustion system is used
C. A condenser is used
D. All of the above
Answer : D

42. 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

43. A thin mild steel wire is loaded by adding loads in equal increments till it breaks. The extensions noted with increasing loads ill behave as under
A. Uniform throughout
B. Increase uniformly
C. First increase and then decrease
D. Increase uniformly first and then increase rapidly
Answer : D

44. The gas constant (R) is equal to the
A. Sum of two specific heats
B. Difference of two specific heats
C. Product of two specific heats
D. Ratio of two specific heats
Answer : B

45. Otto cycle is also known as
A. Constant pressure cycle
B. Constant volume cycle
C. Constant temperature cycle
D. Constant temperature and pressure cycle
Answer : B

46. The ratio of elongation in a prismatic bar due to its own weight (W) as compared to another similar bar carrying an additional weight (W) will be
A. 1 : 2
B. 1 : 3
C. 1 : 4
D. 1 : 2.5
Answer : B

47. Select the correct statement as per Charles' law
A. p.v = constant, if T is kept constant
B. v/T = constant, if p is kept constant
C. p/T = constant, if v is kept constant
D. T/p = constant, if v is kept constant
Answer : B

48. When a system changes its state from one equilibrium state to another equilibrium state, then the path of successive states through which the system has passed, is known as
A. Thermodynamic law
B. Thermodynamic process
C. Thermodynamic cycle
D. None of these
Answer : B

49. When a body is subjected to biaxial stress i.e. direct stresses (?_x) and (?_y) in two mutually perpendicular planes accompanied by a simple shear stress (?_xy), then minimum normal stress is
A. (?_x + ?_y)/2 + (1/2) × ?[(?_x - ?_y)² + 4 ?²_xy]
B. (?_x + ?_y)/2 - (1/2) × ?[(?_x - ?_y)² + 4 ?²_xy]
C. (?_x - ?_y)/2 + (1/2) × ?[(?_x + ?_y)² + 4 ?²_xy]
D. (?_x - ?_y)/2 - (1/2) × ?[(?_x + ?_y)² + 4 ?²_xy]
Answer : B

50. Which of the following is an intensive property of a thermodynamic system?
A. Volume
B. Temperature
C. Mass
D. Energy
Answer : B