1. What type of stress is primarily responsible for causing torsion in shafts?
a) Compressive stress
b) Tensile stress
c) Shear stress
d) Bending stress
Answer: c) Shear stress
Explanation: Torsion in shafts occurs due to the application of twisting forces, resulting in shear stress along the cross-section of the shaft.
2. Which property of a material is crucial in determining its resistance to torsional deformation?
a) Tensile strength
b) Modulus of elasticity
c) Ductility
d) Hardness
Answer: b) Modulus of elasticity
Explanation: Modulus of elasticity (also known as Young’s modulus) represents a material’s stiffness and its resistance to deformation under applied load, including torsional forces.
3. What is the deformation pattern in a circular shaft subjected to torsion?
a) Linear deformation
b) Radial deformation
c) Axial deformation
d) Angular deformation
Answer: d) Angular deformation
Explanation: Torsion in a circular shaft causes angular deformation or twist along its length due to the applied torque.
4. The angle of twist in a shaft is directly proportional to which of the following factors?
a) Length of the shaft
b) Diameter of the shaft
c) Applied torque
d) Modulus of elasticity
Answer: c) Applied torque
Explanation: The angle of twist in a shaft is directly proportional to the applied torque and the shaft’s length, as per the torsion formula.
5. In a stepped transmission shaft, what purpose does the change in diameter serve?
a) Increase torsional strength
b) Reduce weight
c) Improve aesthetics
d) Enhance heat dissipation
Answer: a) Increase torsional strength
Explanation: A stepped transmission shaft increases torsional strength by distributing stresses more evenly along its length, preventing stress concentration at a single point.
6. What advantage does a hollow transmission shaft offer over a solid one?
a) Greater torsional stiffness
b) Lower manufacturing cost
c) Reduced weight
d) Increased durability
Answer: c) Reduced weight
Explanation: A hollow transmission shaft reduces weight while maintaining sufficient torsional strength, making it advantageous for applications where weight is a critical factor.
7. What effect does increasing the shaft diameter have on its torsional resistance?
a) Decreases torsional resistance
b) Increases torsional resistance
c) No effect on torsional resistance
d) Reduces the angle of twist
Answer: b) Increases torsional resistance
Explanation: Increasing the shaft diameter increases its cross-sectional area, thereby increasing its resistance to torsional forces.
8. Which type of stress is predominant in a transmission shaft subjected to torsion?
a) Tensile stress
b) Compressive stress
c) Shear stress
d) Bending stress
Answer: c) Shear stress
Explanation: Shear stress is predominant in a transmission shaft subjected to torsion, as torsional forces create shear stresses along the shaft’s cross-section.
9. What is the primary function of transmission shafts in mechanical systems?
a) Transfer linear motion
b) Transmit rotational motion and torque
c) Provide structural support
d) Act as a heat sink
Answer: b) Transmit rotational motion and torque
Explanation: Transmission shafts are primarily designed to transmit rotational motion and torque from one component to another within mechanical systems.
10. Which material property is crucial for selecting a suitable material for transmission shafts?
a) Electrical conductivity
b) Thermal expansion coefficient
c) Yield strength
d) Refractive index
Answer: c) Yield strength
Explanation: Yield strength is essential for selecting a material with adequate mechanical strength to withstand the torsional stresses experienced by transmission shafts in operation.