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

1. An isothermal process is governed by
A. Boyle's law
B. Charles' law
C. Gay-Lussac law
D. Avogadro's law
Answer : A

2. The amount of heat required to raise the temperature of 1 kg of water through one Kelvin is called
A. Specific heat at constant volume
B. Specific heat at constant pressure
C. kilo-Joule
D. None of these
Answer : C

3. Slenderness of a column is zero when
A. Ends are firmly fixed
B. Column is supported on all sides throughout the length
C. Length is equal to radius of gyration
D. Length is twice the radius of gyration
Answer : D

4. The specific heat at constant volume is
A. The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant pressure
B. The amount of heat required to raise the temperature of unit mass of gas through one degree, at constant volume
C. The amount of heat required to raise the temperature of 1 kg of water through one degree
D. Any one of the above
Answer : B

5. The general law for the expansion or compression of gases, is
A. pv = C
B. pv = m R T
C. pvⁿ = C
D. pv^? = C
Answer : C

6. Kelvin-Planck's law deals with
A. Conservation of work
B. Conservation of heat
C. Conversion of heat into work
D. Conversion of work into heat
Answer : C

7. 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

8. The thickness of a thin cylindrical shell with hemispherical ends is __________ that of spherical ends.
A. Equal to
B. More than
C. Less than
D. None of these
Answer : B

9. The efficiency of Diesel cycle approaches to Otto cycle efficiency when
A. Cut-off is increased
B. Cut-off is decreased
C. Cut-off is zero
D. Cut-off is constant
Answer : C

10. One Joule (J) is equal to
A. 1 N-m
B. 1 kN-m
C. 10 N-m/s
D. 10 kN-m/s
Answer : A

11. 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

12. 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

13. Tensile strength of a material is obtained by dividing the maximum load during the test by the
A. Area at the time of fracture
B. Original cross-sectional area
C. Average of (A) and (B)
D. Minimum area after fracture
Answer : B

14. High air-fuel ratio in gas turbines
A. Increases power output
B. Improves thermal efficiency
C. Reduces exhaust temperature
D. Do not damage turbine blades
Answer : C

15. A series of operations, which takes place in a certain order and restore the initial conditions at the end, is known as
A. Reversible cycle
B. Irreversible cycle
C. Thermodynamic cycle
D. None of these
Answer : C

16. The shape of cantilever for uniformly distributed load will be
A. Straight line
B. Parabolic
C. Elliptical
D. Cubic
Answer : B

17. The buckling load for a given column depends upon
A. Area of cross-section of the column
B. Length and least radius of gyration of the column
C. Modulus of elasticity for the material of the column
D. All of the above
Answer : D

18. Steam coal is a
A. Pulverised coal
B. Brown coal
C. Coking bituminous coal
D. Non-coking bituminous coal
Answer : D

19. Workdone during adiabatic expansion is given by (where p₁ v₁, T₁ = Pressure, volume and temperature for the initial condition of gas, p_2, v₂, T₂ = Corresponding values for the final condition of gas, R = Gas constant, and ? = Ratio of specific heats)
A. (p₁ v₁ - p₂ v₂)/(? - 1)
B. [m R (T₁ - T₂)] /(? - 1)
C. [m R T₁/(? - 1)][1 - (p₂ v₂ /p₁ v₁)]
D. All of these
Answer : D

20. 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

21. The process is adiabatic, if the value of n in the equation pvn = C, is
A. 0
B. 1
C. ?
D. ?
Answer : C

22. When a thin cylindrical shell is subjected to an internal pressure, the volumetric strain is (where ?? = Hoop strain, and ?? = Longitudinal strain)
A. 2?? - ??
B. 2?? + ??
C. 2?? - ??
D. 2?? + ??
Answer : B

23. The shear force diagram for a simply supported beam carrying a uniformly distributed load of w per unit length, consists of
A. One right angled triangle
B. Two right angled triangles
C. One equilateral triangle
D. Two equilateral triangles
Answer : B

24. The isothermal and adiabatic processes are regarded as
A. Reversible process
B. Irreversible process
C. Reversible or irreversible process
D. None of these
Answer : A

25. True stress strain-curve for materials is plotted between
A. Load/original cross-sectional area and change in length/original length
B. Load/ instantaneous cross-sectional area and loge (original area/ instantaneous area)
C. Load/ instantaneous cross-sectional area and change in length/ original length
D. Load/ instantaneous area and instantaneous area/original area
Answer : B

26. Reversed joule cycle is called
A. Carnot cycle
B. Rankine cycle
C. Brayton cycle
D. Bell Coleman cycle
Answer : C

27. Two shafts 'A' and 'B' transmit the same power. The speed of shaft 'A' is 250 r.p.m. and that of shaft 'B' is 300 r.p.m.
A. The shaft 'B' has the greater diameter
B. The shaft 'A' has the greater diameter
C. Both are of same diameter
D. None of these
Answer : B

28. Proof resilience per material is known as
A. Resilience
B. Proof resilience
C. Modulus of resilience
D. Toughness
Answer : C

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

30. Brayton cycle consists' of following four processes
A. Two isothermals and two isentropic
B. Two isentropic and two constant volumes
C. Two isentropic, one constant volume and one constant pressure
D. Two isentropic and two constant pressures
Answer : D

31. The extension of a circular bar tapering uniformly from diameter d? at one end to diameter d? at the other end and subjected to an axial pull of P is given by
A. ?l = 4PE/ ?l²
B. ?l = 4?ld²/PE
C. ?l = 4Pl/?Ed?d?
D. ?l = 4PlE/ ?d?d?
Answer : C

32. The strain energy stored in a solid circular shaft in torsion, subjected to shear stress (?), is: (Where, G = Modulus of rigidity for the shaft material)
A. ?²/ 2G × Volume of shaft
B. ?/ 2G × Volume of shaft
C. ?²/ 4G × Volume of shaft
D. ?/ 4G × Volume of shaft
Answer : C

33. The work ratio of a gas turbine plant 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 : A

34. 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

35. 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

36. According to kinetic theory of gases, the velocity of molecules __________ with the increase in temperature.
A. Remains constant
B. Increases
C. Decreases
D. None of these
Answer : B

37. When a gas is heated at constant pressure
A. Its temperature will increase
B. Its volume will increase
C. Both temperature and volume will increase
D. Neither temperature not volume will increase
Answer : C

38. In the below figure, the stress corresponding to point D is

A. Yield point stress
B. Breaking stress
C. Ultimate stress
D. Elastic limit
Answer : C

39. 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

40. When gas is heated at constant pressure, the heat supplied is utilised in
A. Increasing the internal energy of gas
B. Doing some external work
C. Increasing the internal energy of gas and also for doing some external work
D. None of the above
Answer : C

41. The processes occuring in open system which permit the transfer of mass to and from the system, are known as
A. Flow processes
B. Non-flow processes
C. Adiabatic processes
D. None of these
Answer : A

42. A bar of copper and steel form a comosite 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

43. 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

44. The pull required to tear off the plate per pitch length is (where p = Pitch of rivets, t = Thickness of plates, and ?t, ? and ?c = Permissible tensile, shearing and crushing stresses respectively)
A. (p - 2d) t × ?_c
B. (p - d) t × ?
C. (p - d) t × ?_t
D. (2p - d) t × ?_t
Answer : C

45. 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

46. 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

47. The heat and work are mutually convertible. This statement is called __________ law of thermodynamics.
A. Zeroth
B. First
C. Second
D. Third
Answer : B

48. 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

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. When a body is subjected to three mutually perpendicular stresses, of equal intensity, the ratio of direct stress to the corresponding volumetric strain is known as
A. Young's modulus
B. Modulus of rigidity
C. Bulk modulus
D. Poisson's ratio
Answer : C