Strength of Materials 1000+ MCQ with answer for RBI Assistant

1. The property of a working substance which increases or decreases as the heat is supplied or removed in a reversible manner, is known as
A. Enthalpy
B. Internal energy
C. Entropy
D. External energy
Answer : C

2. A closely-coiled helical spring is cut into two halves. The stiffness of the resulting spring will be
A. Same
B. Double
C. Half
D. One-fourth
Answer : B

3. 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

4. The unit of Young's modulus is
A. mm/mm
B. kg/cm
C. Kg
D. kg/cm²
Answer : D

5. The value of shear stress which is induced in the shaft due to the applied couple varies
A. From maximum at the centre to zero at the circumference
B. From zero at the centre to maximum at the circumference
C. From maximum at the centre to minimum at the circumference
D. From minimum at the centre to maximum at the circumference
Answer : B

6. 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

7. When a body is subjected to a direct tensile stress (?x) in one plane accompanied by a simple shear stress (?xy), the minimum normal stress is
A. (?_x/2) + (1/2) × ?(?_x² + 4 ?²_xy)
B. (?_x/2) - (1/2) × ?(?_x² + 4 ?²_xy)
C. (?_x/2) + (1/2) × ?(?_x² - 4 ?²_xy)
D. (1/2) × ?(?x² + 4 ?²_xy)
Answer : B

8. 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

9. A cantilever beam is one which is
A. Fixed at both ends
B. Fixed at one end and free at the other end
C. Supported at its ends
D. Supported on more than two supports
Answer : B

10. The molecular mass expressed in gram (i.e. 1 g - mole) of all gases, at N. T. P., occupies a volume of
A. 0.224 litres
B. 2.24 litres
C. 22.4 litres
D. 224 litres
Answer : C

11. One molecule of oxygen consists of __________ atoms of oxygen.
A. 2
B. 4
C. 8
D. 16
Answer : A

12. When a closely-coiled helical spring of mean diameter (D) is subjected to an axial load (W), the stiffness of the spring is given by
A. Cd?/D³n
B. Cd?/2D³n
C. Cd?/4D³n
D. Cd?/8D³n
Answer : D

13. 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

14. A fletched beam is used to
A. Change the shape of the beam
B. Effect the saving in material
C. Equalise the strength in tension and compression
D. Increase the cross-section of the beam
Answer : C

15. Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle
A. Combustion is at constant volume
B. Expansion and compression are isentropic
C. Maximum temperature is higher
D. Heat rejection is lower
Answer : D

16. 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

17. The root mean square velocity of the gas molecules is given by (where k = Boltzmann's constant, T = Absolute temperature, and m = Mass of one molecule of a gas)
A. ?(KT/m)
B. ?(2KT/m)
C. ?(3KT/m)
D. ?(5KT/m)
Answer : C

18. One kg of carbon monoxide requires _______kg of oxygen to produce 11/7 kg of carbon dioxide gas.
A. 11/7
B. 9/7
C. 4/7
D. All of the above
Answer : C

19. Resilience of a material is considered when it is subjected to
A. Frequent heat treatment
B. Fatigue
C. Creep
D. Shock loading
Answer : D

20. 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

21. 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

22. Which of the following is a proper sequence?
A. Proportional limit, elastic limit, yielding, failure
B. Elastic limit, proportional limit, yielding, failure
C. Yielding, proportional limit, elastic limit, failure
D. None of the above
Answer : A

23. 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

24. When both ends of a column are fixed, the effective length is
A. Its own length
B. Twice its length
C. Half its length
D. 1/?2 × its length
Answer : C

25. 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 maximum 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 : A

26. A circular shaft fixed at, A has diameter D for half of its length and diameter D/2 over the other half, as shown in the below figure. If the rotation of B relative to A is 0.1 radian, the rotation of C relative to B will be

A. 0.4 radian
B. 0.8 radian
C. 1.6 radian
D. 3.2 radian
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. A concentrated load is one which
A. Acts at a point on a beam
B. Spreads non-uniformly over the whole length of a beam
C. Spreads uniformly over the whole length of a beam
D. Varies uniformly over the whole length of a beam
Answer : A

29. 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

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

31. 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

32. According to Euler's column theory, the crippling load for a column of length (l) with one end fixed and the other end free is __________ the crippling load for a similar column hinged at both the ends.
A. Equal to
B. Less than
C. More than
D. None of these
Answer : B

33. 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

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

35. 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

36. 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

37. The main cause for the irreversibility is
A. Mechanical and fluid friction
B. Unrestricted expansion
C. Heat transfer with a finite temperature difference
D. All of the above
Answer : D

38. Strain is defined as the ratio of
A. Change in volume to original volume
B. Change in length to original length
C. Change in cross-sectional area to original cross-sectional area
D. Any one of the above
Answer : D

39. In a tensile test, near the elastic limit zone, the
A. Tensile strain increases more quickly
B. Tensile strain decreases more quickly
C. Tensile strain increases in proportion to the stress
D. Tensile strain decreases in proportion to the stress
Answer : A

40. A beam which is fixed at one end and free at the other is called
A. Simply supported beam
B. Fixed beam
C. Overhanging beam
D. Cantilever beam
Answer : D

41. 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

42. 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

43. The pressure exerted by an ideal gas is ________ of the kinetic energy of all the molecules contained in a unit volume of gas.
A. One-half
B. One-third
C. Two-third
D. Three-fourth
Answer : C

44. A column that fails due to direct stress, is called
A. Short column
B. Long column
C. Weak column
D. Medium column
Answer : A

45. If Th is the torque resisting capacity of a hollow shaft and Ts is that of a solid shaft, of the same material, length and weight. Then,
A. Th > Ts
B. Th < Ts
C. Th = Ts
D. None of these
Answer : A

46. The distance between the centres of the rivets in adjacent rows of zigzag riveted joint is known as
A. Pitch
B. Back pitch
C. Diagonal pitch
D. Diametric pitch
Answer : C

47. When the gas is heated at constant volume, the heat supplied
A. Increases the internal energy of the gas and increases the temperature of the gas
B. Does some external work during expansion
C. Both (A) and (B)
D. None of these
Answer : A

48. In the torsion equation T/J = ?/r = G?/ L, the term J/R is called
A. Shear modulus
B. Section modulus
C. Polar modulus
D. None of these
Answer : C

49. In case of an under-reinforced beam, the depth of actual neutral axis is __________ that of the critical neutral axis.
A. Same as
B. Less than
C. Greater than
D. None of these
Answer : B

50. 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