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

1. When a body is subjected to a direct tensile stress (?x) in one plane accompanied by a simple shear stress (?xy), the maximum normal stress i
A. (?x/2) + (1/2) × ?(?x² + 4 ?²xy)
B. (?x/2) - (1/2) × ?(?x² + 4 ?²xy)
C. (?x/2) + (1/2) × ?(?x² - 4 ?²xy)
D. (1/2) × ?(?x² + 4 ?²xy)
Answer : A

2. During a tensile test on a specimen of 1 cm cross-section, maximum load observed was 8 tonnes and area of cross-section at neck was 0.5 cm². Ultimate tensile strength of specimen is
A. 4 tonnes/ cm²
B. 8 tonnes/ cm²
C. 16 tonnes/ cm²
D. 22 tonnes/ cm²
Answer : B

3. When coal is first dried and then crushed to a fine powder by pulverising machine, the resulting fuel is called
A. Wood charcoal
B. Bituminous coal
C. Briquetted coal
D. None of these
Answer : D

4. 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

5. A shaft revolving at ? rad/s transmits torque (T) in Nm. The power developed is
A. T.? watts
B. 2?. T.? watts
C. 2?. T.?/75 watts
D. 2?. T.?/4500 watts
Answer : A

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

7. A key is subjected to side pressure as well at shearing forces. These pressures are called
A. Bearing stresses
B. Fatigue stresses
C. Crushing stresses
D. Resultant stresses
Answer : A

8. The heating of gas at constant volume is governed by
A. Boyle's law
B. Charles' law
C. Gay-Lussac law
D. Avogadro's law
Answer : C

9. The oxygen atom is ________ times heavier than the hydrogen atom.
A. 2
B. 8
C. 16
D. 32
Answer : C

10. Which is the false statement about true stress strain method?
A. It does not exist
B. It is more sensitive to changes in both metallurgical and mechanical conditions
C. It gives a more accurate picture of the ductility
D. It can be correlated with stress strain values in other tests like torsion, impact, combined stress tests etc.
Answer : A

11. Within elastic limit, stress is
A. Inversely proportional to strain
B. Directly proportional to strain
C. Square root of strain
D. Equal to strain
Answer : B

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

13. 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

14. The given figure shows the Mohr's circle of stress for two unequal and like principal stresses (?x and ?y) acting at a body across two mutually perpendicular planes. The normal stress on an oblique section making an angle ? with the minor principle plane is given by

A. OC
B. OP
C. OQ
D. PQ
Answer : C

15. Strain is equal to (where l = Original length, and ?l = Change in length)
A. l/?l
B. ?l/l
C. l.?l
D. l + ?l
Answer : B

16. In a free expansion process,
A. W_{1 - 2} = 0
B. Q_{1 - 2} = 0
C. dU = 0
D. All of these
Answer : D

17. Which of the following statement is correct?
A. The increase in entropy is obtained from a given quantity of heat at a low temperature.
B. The change in entropy may be regarded as a measure of the rate of the availability or unavailability of heat for transformation into work.
C. The entropy represents the maximum amount of work obtainable per degree drop in temperature.
D. All of the above
Answer : D

18. A double strap butt joint with equal straps is
A. Always in single shear
B. Always in double shear
C. Either in single shear or double shear
D. None of these
Answer : B

19. When a closely-coiled helical spring of mean diameter (D) is subjected to an axial load (W), the deflection of the spring (?) is given by (where d = Diameter of spring wire, n = No. of turns of the spring, and C = Modulus of rigidity for the spring material)
A. WD3n/Cd?
B. 2WD3n/Cd?
C. 4WD3n/Cd?
D. 8WD3n/Cd?
Answer : D

20. The total energy of a molecule is shared equally by the various degrees of freedom possessed by it. This law is known as
A. Law of equipartition of energy
B. Law of conservation of energy
C. Law of degradation of energy
D. None of these
Answer : A

21. The atomic mass of oxygen is
A. 12
B. 14
C. 16
D. 32
Answer : C

22. Charles' law states that all perfect gases change in volume by __________ of its original volume at 0°C for every 1°C change in temperature, when pressure remains constant.
A. 1/27th
B. 1/93th
C. 1/173th
D. 1/273th
Answer : D

23. The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as
A. Dual combustion cycle
B. Diesel cycle
C. Atkinson cycle
D. Rankine cycle
Answer : C

24. The maximum shear stress, in the given figure, is equal to __________ of the Mohr's circle.

A. Radius
B. Diameter
C. Circumference
D. Area
Answer : A

25. When a beam is subjected to a bending moment, the strain in a layer is __________ the distance from the neutral axis.
A. Equal to
B. Directly proportional to
C. Inversely proportional to
D. Independent of
Answer : B

26. 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

27. When a bar is cooled to - 5°C, it will develop
A. No stress
B. Shear stress
C. Tensile stress
D. Compressive stress
Answer : C

28. Which of the following gas is mostly used in town for street and domestic lighting and heating?
A. Producer gas
B. Coal gas
C. Mond gas
D. Coke oven gas
Answer : B

29. Resilience is the
A. Energy stored in a body when strained within elastic limits
B. Energy stored in a body when strained up to the breaking of the specimen maximum strain
C. Energy which can be stored in a body
D. None of the above
Answer : D

30. One molecule of oxygen is __________ times heavier than the hydrogen atom.
A. 12
B. 14
C. 16
D. 32
Answer : D

31. The deformation of a bar under its own weight is _________ the deformation, if the same body is subjected to a direct load equal to weight of the body.
A. Equal to
B. Half
C. Double
D. Quadruple
Answer : B

32. Which of the following statement is incorrect?
A. The liquid fuels consist of hydrocarbons.
B. The liquid fuels have higher calorific value than solid fuels.
C. The solid fuels have higher calorific value than liquid fuels.
D. A good fuel should have low ignition point.
Answer : C

33. A cycle consisting of __________ and two isothermal processes is known as Stirling cycle.
A. Two constant pressure
B. Two constant volume
C. Two isentropic
D. One constant pressure, one constant volume
Answer : B

34. A simply supported beam with a gradually varying load from zero at B and w per unit length at A is shown in the below figure. The shear force at B is equal to

A. wl/6
B. wl/3
C. wl
D. 2wl/3
Answer : A

35. 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

36. Which of the following gas has the highest calorific value?
A. Coal gas
B. Producer gas
C. Mond gas
D. Blast furnace gas
Answer : A

37. 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

38. Reversed Joule cycle is known as
A. Carnot cycle
B. Bell-Coleman cycle
C. Rankine cycle
D. Stirling cycle
Answer : B

39. According to Avogadro's law
A. The product of the gas constant and the molecular mass of an ideal gas is constant
B. The sum of partial pressure of the mixture of two gases is sum of the two
C. Equal volumes of all gases, at the same temperature and pressure, contain equal number of molecules
D. All of the above
Answer : C

40. The relation between equivalent length (L) and actual length (l) of a column for both ends fixed is
A. L = l/2
B. L = l/?2
C. L = l
D. L = 2l
Answer : A

41. The air standard efficiency of an Otto cycle is given by (where r = Compression ratio, and ? = Ratio of specific heats)
A. 1 - r^{? - 1}
B. 1 + r^{? - 1}
C. 1 - (1/ r^{? - 1})
D. 1 + (1/ r^{? - 1})
Answer : C

42. 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

43. According to Kelvin-Planck's statement of second law of thermodynamics,
A. It is impossible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work
B. It is possible to construct an engine working on a cyclic process, whose sole purpose is to convert heat energy into work
C. It is impossible to construct a device which operates in a cyclic process and produces no effect other than the transfer of heat from a cold body to a hot body
D. None of the above
Answer : A

44. Energy can neither be created nor destroyed, but it can be transformed from one form to another. This statement is known as
A. Zeroth law of thermodynamics
B. First law of thermodynamics
C. Second law of thermodynamics
D. Kinetic theory of gases
Answer : B

45. The heat absorbed or rejected by the working substance is given by (where ds = Increase or decrease of entropy, T = Absolute temperature, and dQ = Heat absorbed or rejected)
A. ?Q = T.ds
B. ?Q = T/ds
C. dQ = ds/T
D. None of these
Answer : A

46. Which of the following gas has a minimum molecular mass?
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Methane
Answer : C

47. 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

48. When a rectangular beam is loaded transversely, the maximum compressive stress is developed on the
A. Top layer
B. Bottom layer
C. Neutral axis
D. Every cross-section
Answer : B

49. The point of contra flexure is a point where
A. Shear force changes sign
B. Shear force is maximum
C. Bending moment changes sign
D. Bending moment is maximum
Answer : C

50. Which of the following is the extensive property of a thermodynamic system?
A. Pressure
B. Volume
C. Temperature
D. Density
Answer : B