MCQOPTIONS
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MCQOPTIONS
This section includes 57 Mcqs, each offering curated multiple-choice questions to sharpen your Civil Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Maximum shear stress developed on the surface of a solid circular shaft under pure torsion is 160 MPa. If the shaft diameter is doubled, then the maximum shear stress developed corresponding to the same torque will be: |
| A. | 10 MPa |
| B. | 30 MPa |
| C. | 40 MPa |
| D. | 20 MPa |
| Answer» E. | |
| 2. |
A circular shaft subjected to torsion undergoes a twist of 1° in a length of 120 cm. if the maximum shear stress induced is limited to 1000 kg/cm2 and of modulus of rigidity G= 0.8 × 106 kg/cm2, then the radius of the shaft should be |
| A. | \(\frac{\pi }{18}\) |
| B. | \(\frac{\pi }{27}\) |
| C. | \(\frac{18}{\pi }\) |
| D. | \(\frac{27}{\pi }\) |
| Answer» E. | |
| 3. |
A solid circular shaft is to transmit power, P kW when turning N revolutions per min. For a given maximum shear stress, the shaft diameter will be proportional to |
| A. | (P/N)0.31 |
| B. | (P/N)0.33 |
| C. | (P/N)0.67 |
| D. | (P/N)0.3 |
| E. | (P/N)0.5 |
| Answer» C. (P/N)0.67 | |
| 4. |
A solid circular shaft of 20 mm diameter transmits a torque of 1570 Nm. The value of maximum shear stress developed is nearly |
| A. | 1000 MPa |
| B. | 20 MPa |
| C. | 50 GPa |
| D. | 20 GPa |
| Answer» B. 20 MPa | |
| 5. |
A hollow shaft of 20 mm diameter and 16 mm inside diameter is subjected to a torque of 40 Nm. The shear stress at outside of the shaft will be: |
| A. | 53.12 N/mm2 |
| B. | 43.13 N/mm2 |
| C. | 62.52 N/mm2 |
| D. | 34.50 N/mm2 |
| Answer» C. 62.52 N/mm2 | |
| 6. |
A shaft is subjected to a bending moment M = 0.75 kN-m and a twisting moment T = 1 kN-m. The magnitude of equivalent bending moment in shaft is |
| A. | 1.25 kN-m |
| B. | 1.125 kN-m |
| C. | 1.0 kN-m |
| D. | 0.75 kN-m |
| Answer» D. 0.75 kN-m | |
| 7. |
A member is subjected to the combined action of bending 400 N-m and torque 300 N-m. What are the equivalent bending moment and equivalent torque respectively? |
| A. | 450 N-m and 500 N-m |
| B. | 900 N-m and 500 N-m |
| C. | 400 N-m and 500 N-m |
| D. | 900 N-m and 350 N-m |
| Answer» B. 900 N-m and 500 N-m | |
| 8. |
A solid circular shaft is subjected to a bending moment M and torque T simultaneously. Neglecting the effects to stress concentration, the equivalent bending moment is expressed as |
| A. | \(\frac{1}{2}\left\{ {M + \sqrt {{M^2} + {T^2}} } \right\}\) |
| B. | \(\left\{ {\frac{M}{2} + \sqrt {{M^2} + {T^2}} } \right\}\) |
| C. | \(\frac{1}{2}\left\{ {M + \sqrt {{M^2} + {4T^2}} } \right\}\) |
| D. | \(\left\{ {\frac{M}{2} + \sqrt {{M^2} + {4T^2}} } \right\}\) |
| Answer» B. \(\left\{ {\frac{M}{2} + \sqrt {{M^2} + {T^2}} } \right\}\) | |
| 9. |
In the torsion equation \(\frac{T}{J} = \frac{τ }{r} = \frac{{Cθ }}{L}\). The term \(\frac{J}{r}\) is called |
| A. | Shear modulus |
| B. | Section modulus |
| C. | Polar modulus |
| D. | None of the above |
| Answer» D. None of the above | |
| 10. |
A rigid horizontal rod of length 2L is fixed to a circular cylinder of radius R as shown in the figure. Vertical forces of magnitude P are applied at the two ends as shown in the figure. The shear modulus for the cylinder is G and the Young’s modulus is E.The vertical deflection at point A is |
| A. | PL3/(πR4G) |
| B. | PL3/(πR4E) |
| C. | 2PL3/(πR4E) |
| D. | 4PL3/(πR4G) |
| Answer» E. | |
| 11. |
If the equivalent torque in a shaft is 500 Nm and the bending moment is 300 Nm. Calculate the magnitude of the required torque and the equivalent bending moment. |
| A. | 500 Nm and 400 Nm |
| B. | 400 Nm and 400 Nm |
| C. | 400 Nm and 500 Nm |
| D. | 300 Nm and 400 Nm |
| Answer» C. 400 Nm and 500 Nm | |
| 12. |
If a section has moment of inertia Ixx on x-axis and moment of inertia Iyy on the y-axis, then polar moment of inertia at the same section will be- |
| A. | (Ixx + Iyy) / 2 |
| B. | (Ixx - Iyy) / 2 |
| C. | Ixx + Iyy |
| D. | Ixx / Iyy |
| Answer» D. Ixx / Iyy | |
| 13. |
A Semi-circle of radius 'r' is defined in first and fourth quadrants. Write down its coordinates of centroid: |
| A. | \((0,\frac{4r}{3\pi})\) |
| B. | (0,0) |
| C. | \((\frac{4r}{3\pi},0)\) |
| D. | \((\frac{4r}{3\pi},\frac{4r}{3\pi})\) |
| Answer» D. \((\frac{4r}{3\pi},\frac{4r}{3\pi})\) | |
| 14. |
Compare the strengths of solid and hollow shafts both having outside diameter D and hollow shaft having inside diameter of D/2 in torsion. The ratio of strength of solid to hollow shafts in torsion will be |
| A. | 0.5 |
| B. | \(\frac{{16}}{{15}}\) |
| C. | 0.75 |
| D. | 0.25 |
| Answer» C. 0.75 | |
| 15. |
For a circular shaft of diameter d subjected to torque T, the maximum value of the shear stress is: |
| A. | \(\frac{{64T}}{{\pi {d^3}}}\) |
| B. | \(\frac{{32T}}{{\pi {d^3}}}\) |
| C. | \(\frac{{16T}}{{\pi {d^3}}}\) |
| D. | \(\frac{{8T}}{{\pi {d^3}}}\) |
| Answer» D. \(\frac{{8T}}{{\pi {d^3}}}\) | |
| 16. |
A hollow shaft of 16 mm outside diameter and 12 mm inside diameter is subjected to a torque of 40 N-m. The shear stress at the outside and inside of the material of the shaft are respectively |
| A. | 62.75 N/mm2 and 50.00 N/mm2 |
| B. | 72.75 N/mm2 and 54.54 N/mm2 |
| C. | 79.75 N/mm2 and 59.54 N/mm2 |
| D. | 80.00 N/mm2 and 40.00 N/mm2 |
| Answer» C. 79.75 N/mm2 and 59.54 N/mm2 | |
| 17. |
A rectangular hollow section with external dimensions 4 cm by 4 cm and thickness of 1 cm will have its moment of inertia about centroidal X-X axis |
| A. | 21.33 cm4 |
| B. | 1.33 cm4 |
| C. | 256 cm4 |
| D. | 20 cm4 |
| E. | 2.0 cm4 |
| Answer» E. 2.0 cm4 | |
| 18. |
A solid shaft can resist a bending moment of 3.0 kN-m and a twisting moment of 4.0 kN-m together. The maximum torque that can be applied is |
| A. | 7.0 kN-m |
| B. | 3.5 kN-m |
| C. | 4.5 kN-m |
| D. | 5.0 kN-m |
| Answer» E. | |
| 19. |
A solid circular shaft of length 4 m is to transmit 3.5 MW at 200 rpm. If permissible shear stress is 50 MPa, the radius of the shaft is: |
| A. | 1.286 mm |
| B. | 12.86 mm |
| C. | 0.1286 mm |
| D. | 128.6 mm |
| Answer» E. | |
| 20. |
A shaft of diameter (d) subject to a bending moment (M) and a twisting moment (T) at a section. The maximum shear stress is given by the equation |
| A. | \({\tau _{max}} = \frac{{16}}{{\pi {d^3}}}\sqrt {{M^2} + {T^2}} \) |
| B. | \({\tau _{max}} = \frac{{16}}{{{d^3}}}\sqrt {{M^2} + {T^2}} \) |
| C. | \({\tau _{max}} = \frac{{16}}{{\pi {d^3}}}\sqrt {1 + {T^2}} \) |
| D. | \({\tau _{max}} = \frac{{16}}{{\pi {d^3}}}\sqrt {{M^2} + 1} \) |
| Answer» B. \({\tau _{max}} = \frac{{16}}{{{d^3}}}\sqrt {{M^2} + {T^2}} \) | |
| 21. |
A particular section of a shaft is subjected to maximum shear stress equal to 30 N/mm2 and a maximum bending moment of 80 N/mm2. If the yield point in tension for this material is 200 N/mm2 and maximum shear stress theory of failure for static is used, then the factor of safety will be: |
| A. | 2 |
| B. | 1.75 |
| C. | 1.2 |
| D. | 1.5 |
| Answer» B. 1.75 | |
| 22. |
Calculate the total angle of twist for a stepped shaft which is subjected to the torque (T) as shown in the figure below. |
| A. | \(\frac{{Tl}}{{\pi G{d^4}}}\) |
| B. | \(\frac{{66Tl}}{{\pi G{d^4}}}\) |
| C. | \(\frac{{Tl}}{{66G{d^4}}}\) |
| D. | \(\frac{{36Tl}}{{\pi G{d^4}}}\) |
| Answer» C. \(\frac{{Tl}}{{66G{d^4}}}\) | |
| 23. |
A solid circular shaft or diameter 8 mm is exposed to a maximum torque of 64 N-m. What is the shear stress in the shaft? |
| A. | 2000π |
| B. | \(\frac {2000}{\pi}\) |
| C. | \(\frac {2}{\pi}\) |
| D. | \(\frac {20}{\pi}\) |
| E. | 2π |
| Answer» C. \(\frac {2}{\pi}\) | |
| 24. |
Circular beam of uniform strength can be made by varying the diameter in such way that |
| A. | M/Z is constant |
| B. | σ/Y is constant |
| C. | M/R is constant |
| D. | E/R is constant |
| Answer» B. σ/Y is constant | |
| 25. |
A solid shaft is designed to transmit 100 kW while rotating at N r.p.m. If the diameter of the shaft is doubled and is allowed to operate at 2N r.p.m., the power that can be transmitted by the latter shaft is |
| A. | 200 kW |
| B. | 400 kW |
| C. | 800 kW |
| D. | 1600 kW |
| Answer» E. | |
| 26. |
Polar moment of inertia of a solid circular shaft of diameter 'd' is: _____. |
| A. | πd2/4 |
| B. | πd4/64 |
| C. | πd4/32 |
| D. | πd3/64 |
| Answer» D. πd3/64 | |
| 27. |
A shaft can safely transmit 90 kW while rotating at a given speed. If the diameter of the shaft is doubled and speed is halved the previous shaft, the power that can be transmitted by new shaft is |
| A. | 360 kW |
| B. | 90 kW |
| C. | 720 kW |
| D. | 180 kW |
| Answer» B. 90 kW | |
| 28. |
A solid circular shaft of diameter d is subjected to a combined bending moment M and torque, T. The material property to be used for designing the shaft using the relation \(\frac{{16}}{{\pi {d^3}}}\sqrt {{M^2} + {T^2}}\) is |
| A. | Ultimate tensile strength (Su) |
| B. | Tensile yield strength (Sy) |
| C. | Torsional yield strength (Ssy) |
| D. | Endurance strength (Se) |
| Answer» D. Endurance strength (Se) | |
| 29. |
A hollow circular shaft has the diameters 50 cm and 30 cm and is subjected to a torque. If the realized maximum shear stress is 30 N/mm2, what is the applied torque to nearest units? |
| A. | 640 kNm |
| B. | 320 kNm |
| C. | 80 kNm |
| D. | 32 kNm |
| Answer» B. 320 kNm | |
| 30. |
If a circular shaft is subjected to torque T and a bending moment M, the ratio of the maximum shear stress to the maximum bending stress is given by |
| A. | 2M/T |
| B. | 2T/M |
| C. | T/2M |
| D. | M/T |
| Answer» D. M/T | |
| 31. |
A solid shaft of diameter d and length L is fixed at both the ends. A torque, T0 is applied at a distance, L/4 from the left end as shown in the figure given belowThe maximum shear stress in the shaft is |
| A. | \(\frac{{16{T_0}}}{{\pi {d^3}}}\) |
| B. | \(\frac{{12{T_0}}}{{\pi {d^3}}}\) |
| C. | \(\frac{{8{T_0}}}{{\pi {d^3}}}\) |
| D. | \(\frac{{4{T_0}}}{{\pi {d^3}}}\) |
| Answer» C. \(\frac{{8{T_0}}}{{\pi {d^3}}}\) | |
| 32. |
A solid shaft of 80 mm diameter is transmitting 100 kW of power at 200 r.p.m. The maximum shear stress induced in the shaft will nearly be |
| A. | 60 N/mm2 |
| B. | 56 N/mm2 |
| C. | 52 N/mm2 |
| D. | 48 Nmm2 |
| Answer» E. | |
| 33. |
An ‘SS’ tube is inserted into an ‘Al’ tube. They are permanently fixed at one end. The other end is attached to a rigid plate. A torque ‘T’ is applied to the rigid plate. The circumference of the ‘AI’ tube at dia ‘D’ at the plate end with respect to the fixed end rotates by a distance ………….. mm due to torque ‘T’. The polar MOI and Rigidity modulus of AI and SS are JAI, GAI and JSS ,GSS respectively. |
| A. | \(\frac{{DLT}}{{2\left( {{G_{AI}}{J_{AI}} - {G_{SS}}{J_{SS}}} \right)}}\) |
| B. | \(\frac{{DLT}}{{2{G_{AI}}{J_{AI}}}}\) |
| C. | \(\frac{{DLT}}{{2\left( {{G_{AI}}{J_{AI}} + {G_{SS}}{J_{SS}}} \right)}}\) |
| D. | \(\frac{{2DLT}}{{{G_{SS}}{J_{SS}}}}\) |
| Answer» D. \(\frac{{2DLT}}{{{G_{SS}}{J_{SS}}}}\) | |
| 34. |
A solid bar of circular cross-section having a diameter of 40 mm and length of 1.3 m is subjected to torque of 340 N.m. If the shear modulus of elasticity is 80 GPa, the angle of twist between the ends will be |
| A. | 1.26° |
| B. | 1.32° |
| C. | 1.38° |
| D. | 1.44° |
| Answer» B. 1.32° | |
| 35. |
A torsion bar with a spring constant ‘k’ is cut into ‘n’ equal lengths. The spring constant for each portion would be |
| A. | nk |
| B. | kn |
| C. | k/n |
| D. | k1/n |
| Answer» B. kn | |
| 36. |
A 50 mm diameter solid shaft is subjected to both, a bending moment and torque of 300 kN-mm & 200 kN-mm respectively. The maximum shear stress induced in the shaft is: |
| A. | 10.22 MPa |
| B. | 14.69 MPa |
| C. | 146.9 MPa |
| D. | 102.2 MPa |
| Answer» C. 146.9 MPa | |
| 37. |
A circular shaft is subjected to a torque of 50 kN-m. If the permissible shear stress is 40 MPa, then the maximum permissible diameter of the shaft is ______. |
| A. | 18.53 mm |
| B. | 40 mm |
| C. | 28.53 mm |
| D. | 25 mm |
| Answer» B. 40 mm | |
| 38. |
A solid shaft of 100 mm diameter transmits 160 HP at 200 rpm. The modulus of rigidity G = 8 × 105 kg/cm2. Then the maximum angle of twist for a length of 6 meter is |
| A. | 5° |
| B. | 2.5° |
| C. | 3.2° |
| D. | 2° |
| Answer» C. 3.2° | |
| 39. |
Consider a beam with circular cross-section of diameter d. The ratio of the second moment of area about the neutral axis to the section modulus of the area is |
| A. | \(\frac{d}{2}\) |
| B. | \(\frac{{\pi d}}{2}\) |
| C. | d |
| D. | πd |
| Answer» B. \(\frac{{\pi d}}{2}\) | |
| 40. |
A long shaft of diameter d is subjected to twisting moment T at its ends. The maximum normal stress acting at its cross section is equal to |
| A. | zero |
| B. | 16T/(πd3 ) |
| C. | 32T/(πd3) |
| D. | 64T/(πd3) |
| Answer» B. 16T/(πd3 ) | |
| 41. |
Moment of inertia of a circle about XX plane: |
| A. | πd4/64 |
| B. | bd4/64 |
| C. | bd3/12 |
| D. | bh4/12 |
| E. | bh4/16 |
| Answer» B. bd4/64 | |
| 42. |
A solid shaft of diameter 100 mm, length 1000 mm is subjected to a twisting moment T. The maximum shear stress developed in the shaft is 60 N/m2. A hole of 50 mm diameter is now drilled throughout the length of the shaft. To develop a maximum shear stress of 60 N/m2 in the hollow shaft, the torque T must be reduced by |
| A. | T/4 |
| B. | T/5 |
| C. | T/12 |
| D. | T/16 |
| Answer» E. | |
| 43. |
For two geometrically similar shafts of the same material, having diameter ratio 2 ∶ 1, if the smaller one has a torque capacity of 1 kg-m, then the larger one will carry |
| A. | 2 kg-m |
| B. | 4 kg-m |
| C. | 8 kg-m |
| D. | 1 kg-m |
| Answer» D. 1 kg-m | |
| 44. |
A circular steel bar of diameter d and length 3I fixed at both ends is loaded at intermediate section by torques T and 2T as shown in the following figure. The support reactions can be given as |
| A. | MA = T and MB = 2T |
| B. | MA = 2T and MB = T |
| C. | MA = 4T/3 and MB = 5T/3 |
| D. | MA = 5T/3 and MB = 4T/3 |
| Answer» E. | |
| 45. |
A solid shaft can resist a bending moment of 6 kN.m and a torque of 8 kN.m applied together. The maximum torque that the shaft can resist when applied alone is |
| A. | 7 kN.m |
| B. | 48 kN.m |
| C. | 10 kN.m |
| D. | 14 kN.m |
| Answer» D. 14 kN.m | |
| 46. |
If a shaft diameter d is subjected to bending moment M, the bending stress (σb) induced in the shaft is given by: |
| A. | \({\sigma _b} = \left( {\frac{{32M}}{{\pi {d^3}}}} \right)\) |
| B. | \({\sigma _b} = \left( {\frac{{16M}}{{\pi {d^3}}}} \right)\) |
| C. | \({\sigma _b} = \left( {\frac{{32M}}{{\pi {d^2}}}} \right)\) |
| D. | \({\sigma _b} = \left( {\frac{{64M}}{{\pi {d^4}}}} \right)\) |
| Answer» B. \({\sigma _b} = \left( {\frac{{16M}}{{\pi {d^3}}}} \right)\) | |
| 47. |
A tubular shaft, having an inner diameter of 30 mm and an outer diameter of 40 mm, is to be used to transmit 80 kW of power. The speed of rotation of the shaft so that the shear stress will not exceed 50 MPa is |
| A. | 29.6 rpm |
| B. | 3557.4 rpm |
| C. | 1778.7 rpm |
| D. | 59.2 rpm |
| Answer» D. 59.2 rpm | |
| 48. |
In solid shaft, stress at the centre is |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | Average |
| Answer» D. Average | |
| 49. |
A circular shaft of diameter D is subjected to a torque T. The maximum shear stress of the shaft will be |
| A. | proportional to D3 |
| B. | proportional to D4 |
| C. | inversely proportional to D3 |
| D. | inversely proportional to D4 |
| Answer» D. inversely proportional to D4 | |
| 50. |
A hollow shaft of same cross-section area as solid shaft transmits: |
| A. | Same torque |
| B. | Less torque |
| C. | More torque |
| D. | More or less depending on external diameter |
| Answer» D. More or less depending on external diameter | |