Machine Design Objective Questions and Answers - Set 21 - ObjectiveBooks

# Practice Test: Question Set - 21

1. When spring index increases, the value of Wahl's stress factor
(A) Increases linearly
(B) Decreases linearly
(C) Remains same
(D) Increases exponentially

2. In worm gears, the pressure angle is __________ the angle between two inclined faces in axial plane.
(A) Half
(B) Twice
(C) Thrice
(D) None of these

3. A steel containing _________ 0.8% carbon is known as hypo-eutectoid steel.
(A) Equal to
(B) Less than
(C) Greater than
(D) None of these

4. The material commonly used for crane hooks is
(A) Cast iron
(B) Wrought iron
(C) Mild steel
(D) Aluminium

5. A leaf spring in automobiles is used
(A) To apply forces
(B) To measure forces
(C) To absorb shocks
(D) To store strain energy

6. The velocity factor for very accurately cut and ground metallic gears operating at velocities upto __________ are equal to 6/(6 + v).
(A) 10 m/s
(B) 12.5 m/s
(C) 15 m/s
(D) 20 m/s

7. When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be
(A) 4F/ πd²
(B) 6F/ πd²
(C) 8F/ πd²
(D) 16F/ 3πd²

8. According to Indian standards, total numbers of fundamental deviations are
(A) 10
(B) 15
(C) 20
(D) 25

9. The most important dimension in the design of a nut is
(A) Pitch diameter
(B) Inside diameter
(C) Outside diameter
(D) Height

10. When an open coiled helical compression spring is subjected to an axial compressive load, the stress induced in the wire is
(A) Tensile stress
(B) Compressive stress
(C) Shear stress
(D) Bending stress

11. If T₁ and T₂ are the tensions on the tight and slack sides of the belt respectively, and Tc is the centrifugal tension, then initial tension in the belt is equal to
(A) T₁ - T₂ + Tc
(B) T₁ + T₂ + Tc
(C) (T₁ - T₂ + Tc)/2
(D) (T₁ + T₂ + Tc)/2

12. The relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (D) is given by (where T = Number of teeth on the sprocket)
(A) p = D sin (90°/T)
(B) p = D sin (120°/T)
(C) p = D sin (180°/T)
(D) p = D sin (360°/T)

13. Cast iron pipes are mainly used
(A) For conveying steam
(B) In water and sewage systems
(C) In pressure lubrication systems on prime movers
(D) All of the above

14. The modulus of elasticity for mild steel is approximately equal to
(A) 80 kN/mm²
(B) 100 kN/mm²
(C) 110 kN/mm²
(D) 210 kN/mm²

15. If an application calls for stresses on screw threads in one direction only, then the following type of thread would be best suited
(A) Square
(B) Acme
(C) Buttress
(D) BSW

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