Strength of Materials MCQ Solved Paper for LIC AAO

1. Diesel cycle consists of following four processes
A. Two isothermal 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 : C

2. The moment of resistance of a balanced reinforced concrete beam is based on the stresses in
A. Steel only
B. Concrete only
C. Steel and concrete both
D. None of these
Answer : C

3. The universal gas constant (or molar constant) of a gas is the product of
A. Molecular mass of the gas and the gas constant
B. Atomic mass of the gas and the gas constant
C. Molecular mass of the gas and the specific heat at constant pressure
D. Molecular mass of the gas and the specific heat at constant volume
Answer : A

4. The gas turbine cycle with regenerator improves
A. Thermal efficiency
B. Work ratio
C. Avoids pollution
D. None of these
Answer : A

5. When a body is subjected to a direct tensile stress (?x) in one plane accompanied by a simple shear stress (?xy), the maximum shear 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 : D

6. One kilowatt is equal to
A. 1 N-m/s
B. 100 N-m
C. 1000 N-m/s
D. 1 × 10⁶ N-m/s
Answer : C

7. 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

8. 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

9. The natural solid fuel is
A. Wood
B. Coke
C. Anthracite coal
D. Pulverised coal
Answer : A

10. A hollow shaft of same cross-section area as compared to a solid shaft transmit
A. Same torque
B. Less torque
C. More torque
D. Unpredictable
Answer : C

11. 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

12. A process, in which the gas is heated or expanded in such a way that the product of its pressure and volume remains constant, is called
A. Isothermal process
B. Hyperbolic process
C. Adiabatic process
D. Polytropic process
Answer : B

13. Percentage reduction of area in performing tensile test on cast iron may be of the order of
A. 50 %
B. 25 %
C. 0 %
D. 15 %
Answer : C

14. 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

15. In a prismatic member made of two materials so joined that they deform equally under axial stress, the unit stresses in two materials are
A. Equal
B. Proportional to their respective moduli of elasticity
C. Inversely proportional to their moduli of elasticity
D. Average of the sum of moduli of elasticity
Answer : B

16. 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

17. First law of thermodynamics deals with
A. Conservation of heat
B. Conservation of momentum
C. Conservation of mass
D. Conservation of energy
Answer : D

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

19. 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

20. The change in the unit volume of a material under tension with increase in its Poisson's ratio will
A. Increase
B. Decrease
C. Remain same
D. Increase initially and then decrease
Answer : B

21. 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

22. In a belt drive, the pulley diameter is doubled, the belt tension and pulley width remaining same. The changes required in key will be
A. Increase key length
B. Increase key depth
C. Increase key width
D. Double all the dimensions
Answer : C

23. 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

24. 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

25. 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

26. The property of a material which allows it to be drawn into a smaller section is called
A. Plasticity
B. Ductility
C. Elasticity
D. Malleability
Answer : B

27. 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

28. If the radius of wire stretched by a load is doubled, then its Youngs modulus will be
A. Doubled
B. Halved
C. Becomes four times
D. None of the above
Answer : D

29. 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

30. 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

31. 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

32. 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

33. In the below figure, curve D represents_________.

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

34. 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

35. 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

36. The efficiency of the Carnot cycle may be increased by
A. Increasing the highest temperature
B. Decreasing the highest temperature
C. Increasing the lowest temperature
D. Keeping the lowest temperature constant
Answer : A

37. 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

38. Petrol is distilled at
A. 65° to 220°C
B. 220° to 345°C
C. 345° to 470°C
D. 470° to 550°C
Answer : A

39. 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

40. 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

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 /div>